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How to Boost Immunity With Diet and Exercise

by PAUL ROGERS

How many times have you seen an ad for some wonder herb or other that’s supposed to boost the immune system. It’s echinacea today and some Chinese herb the next, as well as a vast array of products that the supplement industry claim “support the immune system” — whatever that means.

Diet and Immunity

I’m not suggesting that diet and nutrition don’t have an important role to play in maintaining a healthy immune system. Meeting the recommended intake of macronutrients, vitamins and minerals and fats, and consuming copious quantities of antioxidant nutrients as part of healthy eating is bound to promote good immune system function — as far as it goes. However, the evidence for consuming individual dietary components or special foods or supplements beyond the RDI (recommended dietary intake) is mostly speculative or at least inconclusive.

Exercise and Immunity

If you follow a healthy lifestyle approach with healthy eating and a program of physical activity, here are a few things to note about how the immune system responds to exercise:

  • A regular, low to moderate intensity exercise habit is associated with a reduced incidence of infection compared with those who do very little exercise or physical activity.
  • Heavy, and or prolonged exercise training can impair the immune system, possibly leading to susceptibility to infection, particularly in a period of up to 24 hours after a heavy training session or event.
  • Exercising at high intensity for prolonged periods without food — 90 minutes and beyond for example — may make you especially vulnerable to infection as a result of immune system depression.
  • Consuming carbohydrate at the rate of 30-60 grams an hour during intense and prolonged exercise can help to maintain immune system function. That’s 1-2 sports drinks and hour or equivalent. (One drink is probably adequate for most situations except for extreme conditions and intensity.)
  • Meeting your daily requirements for micronutrients like zinc, iron, and B and C vitamins is essential. Although a multivitamin supplement may help, consuming mega quantities of vitamins and minerals may be counterproductive. Excess vitamin C may inhibit natural energy production, say above 1000 mg/day.
  • A recent review confirmed the value of carbohydrate supplementation and a possible role for vitamin C (note caution above), but no other supplement showed up as useful for heavy exercisers.

It’s worth noting the value of carbohydrate to immunity in a balanced diet and exercise program. Low-carbohydrate intake with low blood glucose, plus the stresses of exercise, increases cortisol production to the point where the immune system is compromised. Low-carb, high-fat diets, especially saturated fat, are not appropriate if you have a robust exercise program. In addition, saturated fat has been shown to impair immune response. Low-carb is not where you want to be if you exercise a lot.

Red meat and chronic disease

by PAUL ROGERS

Red meat is a dietary staple in developed nations of the west — North America, Europe, Australia and much of South America in the more affluent countries and regions. In fact, eating read meat is almost a badge of affluence. In Asia, red meat is not usually the protein of choice, or availability,  although consumption is rising in countries like Japan and China.

Red meat is defined as beef, pork, lamb, veal and goat in foods like hamburgers, minced beef, pork chops and roast lamb.

Lifestyle diseases, nutrition and red meat

The problem is, individuals with the greatest consumption of red meat — and processed meats like ham, bacon, salami and hot dogs — keep showing up in health studies as having a higher incidence of chronic diseases like cancer, heart disease, diabetes and macular eye degeneration. It seems that consumers of the highest quantities of red meat are more susceptible to these diseases than those who eat the  lowest amounts. And, what makes the data more believable, is that in many studies the same risks do not show up for white meats like chicken, fish and turkey. So what’s going on with red meat?

salad.jpgMost of these investigations are prospective type observational studies where groups of individuals are followed forward in time while their disease outcomes are noted along with their diets. The link between red meat and such diseases cannot really be called “causal” because observational studies like these are not rigorous enough to provide that answer conclusively. Even so, when the same results are found in more than one study, the results become more convincing.

Here are some diseases linked to red meat and processed meat consumption, although not all conclusively.

  • Cancer – bowel (colorectal) and perhaps breast and prostate
  • Type 2 diabetes
  • Cardiovascular disease
  • Macular eye degeneration

An example of how reducing red meat consumption can improve health is demonstrated by a study in which reducing the amount of red meat in the diet improved kidney function substantially in type  2 diabetics as measured by the urinary albumin excretion rate. (de Mello et al.)

 Is it red meat or fewer plant foods?

If these correlations do turn out to be causal, then what is the mechanism of such an effect? There are several candidates.

  • Too much red meat in the diet may result in too few plant foods being ingested and a deficiency of antioxidants, vitamins and minerals that protect against free radicals and other toxic principles. Considering that vegetable protein consumption does not seem to be related to the disease states associated with red meat, this is a reasonable scenario.
  • Heme iron in excess may be toxic. Strange as it may seem, too much iron from red meats may actually cause an excess of free radicals, mutagenic compounds and consequent damage to  all sorts of tissues. This does not seem to be the case with non-heme iron, as in plant sources of iron. There’s more to come on that I’m sure, but it is a favoured causal hypothesis.
  • Burnt meat can contain known carcinogens like polycyclic aromatic hydrocarbons and heterocyclic amines, which might account for colon cancer and other possible cancers.
  • Red  meat as a product of factory farming, feed lots, and various commercial production methods may be contaminated with polychlorinated aromatics like dioxins and PCBs, which are known carcinogens and diabetogens. Free-range and organic production may produce different nutritional profiles.

What you can do to lower the risk

The World Cancer Research Fund recommends limiting consumption of red meat (such as beef, pork and lamb) and avoiding processed meats. They suggest you eat no more than 500 grams (just over a pound), cooked weight per week of red meats, like beef, pork and lamb, and avoid processed meats such as ham, bacon, salami, hot dogs and some sausages. Other sources recommend half this amount or none at all. A medium steak is about 145 grams (about one-third of a pound).

de Mello VD et al. Am J Clin Nutr. 2006 May;83(5):1032-8. Withdrawal of red meat from the usual diet reduces albuminuria and improves serum fatty acid profile in type 2 diabetes patients with macroalbuminuria.

Survival of the fittest – heart and longevity

by PAUL ROGERS

We all know that exercise and physical activity is good for us: authorities have been belting out the message for decades. Even so, it all gets a little confusing trying to decide how much, what type of exercise, and how to know if you’re doing enough by any measurable parameter.

But we do have some real numbers to work with.

Kodama and colleagues at the Department of Internal Medicine, University of Tsukuba in Japan completed a meta-analysis of cardiorespiratory fitness as a predictor of all-cause mortality and cardiovascular events in healthy men and women. (A meta-analysis combines all relevant studies focusing on a particular outcome and analyses the collective results.) Thirty-three studies were included in the analysis.

Fitness lowers heart attack risk and increases longevity

Running and joggingThe results were quite informative, even though these types of observational study cannot provide too much certainty at the detail level. However, we do know that fitness generally has positive, preventive effects on heart disease and some cancer risks, and possibly other longevity factors such as immunity, but this study gave us some practical working numbers in terms of  fitness and performance. The researchers classified participants by their measured fitness and aerobic power in terms of METS or metabolic equivalents.

A MET is the amount of  energy consumed at rest and 8 METS would be the ability to exercise at 8 times the energy expenditure of sitting still, or the ‘resting metabolic rate’. Participants were categorized as low cardiorespiratory fitness (CRF) (less than 7.9 METs), intermediate CRF (7.9-10.8 METs), or high CRF (greater than or = 10.9 METs).rmance by age group. Here are the results:

  1. Compared with participants with high CRF, those with low CRF had a relative risk for all-cause mortality of 1.70; and for CHD/CVD events of 1.56.
  2. Compared with participants with intermediate CRF, those with low CRF had a relative risk for all-cause mortality of 1.40 and for CHD/CVD events of 1.47

Those risk numbers, 1.70 and 1.56, for example, describe the increase in risk comparing those with lower fitness (1.70, 1.56) to those with higher fitness 1.0, 1.0). You can see that as you get fitter, your risks of a heart event (heart attack or stroke or similar) or death decrease rather dramatically. Or, you can look at it the other way around: the less fit you are, the greater your risks of a heart event or death compared to a much fitter person.

What this means in practical terms

Why this study is so useful is that the authors interpreted the results in language  that is explanatory to non-specialists. For example, the minimum cardiorespiratory fitness level that seems to be protective is 9 METs for men at age 40, 8 METs for men at age 50, and 7 METs for men at age 60. For women, it is 7 METs at age 40, 6 METs at age 50, and 5 METs at age 60.

To translate this into walking or jogging speeds, based on Kodama’s data, the speeds would be (in miles or kilometres per hour):

8 METS — 4 mph or 6.4 kmh (very fast walk)

10 METS — 5 mph or 8.0 kmh (slow jog)

12 METS — 6 mph or 9.6 kmh (jog)

If, at 60, you can do 6 miles or 10 km in an hour (12 METS), then you are in the super fit category, because this would even be highly protective fitness for a 40-year old — according to the data from this study.

This is encouraging for people who are not really into hard-core fitness programs. You do have to be fit to walk at 8 METS for an hour, but not exceptionally so. A regular walking program will likely see you achieve this performance well past age 60. For comparison, an amateur fun runner or marathon runner can run at 15 to 18 METS for an hour, and professional endurance athletes at up to 25 METS!

Add a few sessions of weight training per week for muscle maintenance — at home will do — to your regular walking or jogging, and you can see that keeping fit needs commitment, but it does not have to be too onerous. #

–Kodama S, Saito K, Tanaka S, et al. Cardiorespiratory fitness as a quantitative predictor of all-cause mortality and cardiovascular events in healthy men and women: a meta-analysis. JAMA. 2009 May 20;301(19):2024-35.

What you need to know about burning fat

by PAUL ROGERS

The idea of ‘fat burning’ has become something of a cliché these days. I’m not surprised. It sounds logical that if you want to lose weight you should burn up that body fat that makes you fat . . . right?

In a way that’s correct, but what has been grossly misunderstood is that you don’t have to ‘target’ fat burning during exercise with low to medium effort because, as the mythology goes, that is the ‘fat-burning’ zone.

So what really happens with your metabolism as you exercise in relation to the use of fat as a fuel?

How Fat Burning Works During Exercise

Energy in, energy out. The body normally burns a mix of carbohydrate, as glucose, and fat for fuel. How much of either depends on your physical activity and if, or what you have eaten recently. When you use more energy than you take in from food and drink, the body burns stored fat and carbohydr

Running

ates, and then even uses protein, to fuel your everyday activities even if you are not exercising.

That’s what happens when people starve of course; the body starts to eat itself. Depending on your family history — your genetics — and the way you eat and exercise to create this energy deficit, your body may decide to get conservative and drop your metabolic rate to try to hold onto body weight. Some of us seem to have inherited this tendency more than others, the origins of which may be in the early periods of human evolution where ‘feast or famine’ was more or less the norm.

Glucose, fat and protein. Even so, starvation always works eventually and the body starts to break down its own tissue for fuel. Stored carbohydrate called glycogen is quickly used up, then goes the fat stored under the skin and around the internal organs. Protein in muscle is then broken down to create glucose to keep the brain working and you conscious.

Fat and glucose are the body’s two main energy sources. Fat you know well, glucose comes mainly from carbohydrate foods like rice and bread and potatoes and protein is supplied mainly by meat and beans and dairy products. The amino acid building blocks of protein foods can be converted to glucose in emergencies. Your body always burns a mix of fat and glucose except at very high intensities, and the ratio of the fat and glucose in ‘the burn’ varies with intensity and time of exercise.

Fat burning zone. You may have noticed that some bikes and treadmills at the gym have a setting that says ‘fat burning zone’, which implies a setting for intensity or speed. The reason for this is that the body burns a greater percentage of fat at a slow pace (or after about 90 minutes of exercise). The fat burning zone, a low intensity speed zone, is mainly a gimmick, and here is the reason.

Even though you burn more fat going slowly, you still burn some fat at much faster speeds or intensity. It all boils down to how much energy you expend in totality. For example, if you compare exercising at a slow rate that burns 60 percent fat and 40 percent glucose and a higher intensity or duration that burns only 30 percent fat and 70 percent glucose, you may still burn more fat at the higher intensity.

A typical example. Exercise (1) is the slower 60/40 mix and exercise (2) is the faster, 30/70 mix of fat and glucose fuel.

  1. Walking on a treadmill for 30 minutes — 180 calories used — 108 calories of fat burned
  2. Running on a treadmill for 30 minutes — 400 calories used — 120 calories of fat burned

You can see from this example that the bottom line really is how much energy you expend — and that is the ultimate fat burning measure. The theoretical fat burning zone is mostly a convenient myth.

How Fat Burning Works After Exercise

Now here’s the thing most people don’t consider. Even allowing for that little calculation above on how much fat you use to fuel any activity, energy use and fat burning needs to be seen as a continuum over an extended period. Twenty-four hours is a nice round number. You need to consider what happens after you stop exercising as well as when you are exercising. Here’s one thing that happens when you exercise at higher intensities, say above 75% of maximum heart rate. As you use glucose for energy at higher intensities, your blood, liver  and muscle glucose (glycogen) falls somewhat — and of course this is tricky for endurance athletes like marathoners because glucose is a more empowering fuel up to 2 hours or so of racing than fat. But then, when you stop exercising and you have low blood and muscle glucose, insulin is low, the hormone glucagon is rising and so is hormone-sensitive lipase, a hormone that promotes the break-up of fat triglycerides to free fatty acids for fuel. Fat burning is prioritised, even though eventually you will replenish glucose stores with food and you will start to burn a little more glucose and less fat. It’s a cyclical process. You might even prolong this fat burning phase by eating low-glycemic index foods after your workout.

What You Need to Do to Burn Fat

The main point here is that you don’t have to worry about fat-burning zones and exercising at a mythical fat-burning intensity for weight loss. It all gets sorted out over a 24-hour period as the priority fuels fat and glucose wax and wane according to physical activity intensity and food intake. All you need to be concerned about for weight loss is energy expenditure, and, of course, creating an energy deficit, which means not pigging out after your workout and destroying all your hard work. #

How to improve restrictive diets with a few tweaks – low-carb, low-fat, vegan

I’m not a big fan of low-carbohydrate diets, or most restrictive diets that target one macronutrient for that matter. For one thing, I’ve been doing hard exercise since I was 10 years old and I’m not about to stop anytime soon. You need optimal quantities of carbohydrates and a reasonable quantity of quality fats and protein for health and performance: ask any professional sports nutritionist or athlete. (As opposed to some of the quacks one reads on the net.)

Even so, healthy eating requires that you eat a good proportion of those carbs and fats as quality carbohydrates and fats and proteins —  fibrous wholegrains, fruits and vegetables, beans and nuts, or lean meats, and unsaturated oils.

AvocadoBut let’s say you like low-carb Atkins type diets (20% carbohydrate) or an Ornish very low-fat diet (10% fat) or a vegan diet with no animal products; yet some aspects of the diet just doesn’t work for you and you struggle to stay with it, which is not surprising because less than 10 percent of people who try such restrictive diets actually maintain them for more than about 6 months.

For example, you don’t exercise well on low-carb or you get too lean and lose some muscle on very low-fat or vegan. The answer to this problem is just to move the baseline a little to modify the existing diet to a point where you can follow, more or less, the general principles of the regimen you like, yet maintain a quality eating pattern day in, day out. You adjust the eating rules so that the pattern moves closer to what you’re comfortable with, yet without compromising dietary quality or your preference for that particular dietary style. You do this by implementing healthy eating principles within the confines of your dietary approach. Here’s how you might do this with various restrictive diets.

How to improve a low-carbohydrate diet and stay on track

Low-carbohydrate diets are still somewhat popular, although many followers are moving emphasis to healthy fats and a little more quality carbohydrate in order to sustain them. I will ignore keto diets here because they don’t have much scientific credibility for the general public.

1. Increase carbohydrate consumption to around 40% of total energy intake.
2. Keep saturated fat and trans fats low (under 10% saturated and trans). This means choosing lean and low-fat animal foods and including more vegetable protein.
3. Include plenty of high-fibre or low-GI carbohydrate and eat more fruit. If you don’t like wheat or gluten, eat wholegrain rice, buckwheat or polenta, and choose more berries or low-carbohydrate fruits like oranges or other citrus.
4. Some might argue that 40% is not low-carb, but this site is not called Food, Fit, Fusion for nothing — I expect an exercise program — and this is the minimum quantity of carbohydrate you can get away with if you want to hit the workout hard, week in, week out. Even then, it is probably not ideal for many heavy exercisers.

How to improve a very low-fat diet and stay on track

Ornish very low-fat diets have been used in heart disease rehabilitation with some degree of success. The Pritikin Diet of 20 or more years ago was very similar. At 10-12% dietary fat, this is a very restrictive diet for most people. A few changes might not alter the overall utility, and may even improve the success of it for most people.

1. Increase fat intake from 10% to around 20% of total energy of the diet.
2. Add some wholefood vegetable fats like avocado, and nuts like almonds, Brazil nuts and walnuts. You can keep the screws on added oils and just increase plant-based fats in whole foods.
3. Avoid plant sources with saturated fats, for example palm oil and coconut oil.
4. Continue to avoid added sugars and refined carbohydrate foods.

How to improve a vegan diet and stay on track

Vegans eat no animal foods at all — meat, eggs or dairy. A little care is required to get the best out of a vegan diet.

1. We’ll make similar changes to the vegan diet as for the very low-fat, Ornish type diet – without the meat and dairy. Aim for at least a 20% fat diet.
2. In my experience, vegans often under-eat, especially those who do a reasonable amount of exercise. The quantity of fibre in vegan diets can be up around the 50 to 60 grams/day mark, about 3 times the average intake. This amount of fibre, although likely a healthy quantity, is very filling and can reduce appetite.
3. The dietary constituents on the low side – other than the sometimes deficient B12 — are likely to be fat and protein, especially for raw food vegans or, unusually, fruitarians. Vegans should ensure they consume plenty of nuts, avocado, bean foods, plant milks (not coconut) and the regular stir fry — and not get into the habit of existing on salads, fruits and bread and cereals and pasta.

Summing up

There you have it — your cake and eat it too — as long as it’s a bran and blueberry oat cake.

Prevent prostate cancer with diet, exercise and lifestyle change

by PAUL ROGERS

Preventing prostate cancer with lifestyle behaviours may not be that extreme a proposition considering the latest research from a group studying gene and prostate cancer interactions.

I should make it perfectly clear that this research is promising and profoundly interesting, but it is not a sure-fire cure for prostate cancer and you should not disregard advice from your treatment specialist if you have existing prostate cancer.

The prostate is a gland that sits at the neck of the urethra and bladder in men and the cancer usually occurs in men older than 40 and with increasing incidence as men age.

The study emphasized a diet high in plant foods and exercise

Fresh plant foodsThe pilot study, which involved well-known lifestyle researcher and nutritionist, Dr Dean Ornish, evaluated changes in prostate gene expression in men with low-risk prostate cancer who declined conventional treatments like surgery, hormone therapy or radiation and who trialed an intensive nutrition and exercise lifestyle program while undergoing evaluation for tumor progression.

The patients at a diet high in plant foods including soy, the mineral selenium and vitamins C and E and very little of red meat and fats. They walked or did gym for at least 30 minutes, 6 days a week; did an hour of daily yoga or meditation type relaxation; and attended 1-hour weekly support sessions.

The authors emphasize that it is too early to know if this kept the cancer in check. Yet, to the surprise of the researchers, what they found was that at the gene level, genes that protect against cancer seemed to be turned on (tumor-suppressor genes) and genes that promote cancer (oncogenes) were turned off in substantial quantities.

University of California, San Francisco geneticist Christopher Haqq said”

“It is absolutely intriguing this lifestyle change can have as much effect as the most powerful drugs available to us now. We medical oncologists are always looking for drugs that can do this. It is delightful to find that diet and lifestyle can have profound effects and be complementary to drug therapies—with fewer side effects.”

What you need to know

While this looks like a valuable line of research, don’t get too carried away and reject all standard treatments if your doc advises it is too dangerous to do so. Remember that the experimental group had “low-risk” of prostate cancer to start with.

Second, what this research does suggest is that this sort of lifestyle approach could be a really useful preventive approach to prostate cancer. You need to get that exercise and eat lots of nuts, beans, seeds like sunflower and pumpkin green vegetables, fruits and whole grains. Avoid the red meat and saturated fat as much as possible. A few Brazil nuts each day will give you a good dose of natural selenium — about 100 micrograms or thereabout.

Read more at Proceedings of the National Academy of Sciences,  and Lancet Oncology.

Ten Ways Exercise Prevents or Manages Diabetes

by PAUL ROGERS

Trials in the US, Finland and China have shown that moderate weight loss combined with an exercise program can ward off impending type 2 diabetes by getting blood glucose (sugar) under control and generally improving markers for this disease of glucose, fat and insulin metabolism. Diagnosed diabetics also benefit from regular exercise in a similar way.

Here’s how exercise helps:

  1. Physical activity helps you manage weight. You need to include a sensible eating program, but weight loss improves your ability to process glucose and ward off diabetes.
  2. Exercise uses glucose stored in muscle and, over time and with increased fitness, enhances the amount of glucose you can store, lowering blood glucose in the process.
  3. Weight training uses muscle glucose more than fat, as does other high-intensity exercise. Regular sessions of weight lifting lower your blood glucose and open up the “gates” for glucose transport.
  4. Weight training also builds more muscle. More muscle provides additional storage capacity for glucose.
  5. Glucose transport to muscle during exercise does not require insulin. In fact, insulin goes quiet during exercise in people with normal metabolism and not injecting insulin.
  6. Physical activity enhances insulin sensitivity even when you’re not exercising. Insulin sensitivity is the ability of insulin to store glucose.
  7. Day to day, exercise gives you improved glucose storage when you’re exercising, and improved glucose storage when you’re not. You get a synergy of effect when you exercise.
  8. Cardiovascular fitness is a result of aerobic conditioning. Cardio type exercise is best for this. Heart and lung fitness is associated with protection against diabetes and heart disease. The fitter you are, the better your chances — even allowing for some excess weight.
  9. Faulty fat metabolism and high levels of fat (triglycerides) in the blood raise your chances of getting diabetes. Exercise of any sort can help normalize blood fat levels. Look to be under 150 mg/dL or 1.69 mmol/L. When you’re really fit and healthy and have low overall body fat, this number will be closer to 100 mg/dL (1.1 mmol/L) or less. You should aim for this.
  10. Regular exercise, especially higher-intensity exercise, increases your metabolism when you’re not exercising. This not only helps lower blood fats and glucose, it helps you reach and maintain normal weight.

How robust is your heart and fitness?

By PAUL ROGERS

Heart rate recovery research in relation to cardiovascular health has been around for some time, using various medical and fitness treadmill stress tests like the Bruce or Balke protocols. According to the researchers working in this field, heart rate recovery predicts all-cause mortality in a group without previous serious heart disease who were followed for 12 years — and was a stronger indicator of risk than other established risk factors.

Essentially the test requires you to build up to maximum heart rate and record the recovery time 60 seconds after slowing to a walk.  Although the original research was done on a treadmill using Bruce maximum exercise protocol, you can probably emulate this within reasonable limits down at the local park or on a rowing machine, treadmill or stationary bike.

It is important to understand that if you have been inactive for some time, or have signs of heart disease or a related condition like diabetes, or even if you are not used to exercising at maximum heart rate, then this is not for you. You should do this test or one similar under the supervision of a doctor or cardiologist (perhaps a stress echo) or other appropriately trained medical professional; or at least get a doctor’s approval to do it if you’re unsure.

Here is what to do. I’ll use a running track in this example.

  1. Warm up for 5-10 minutes at a slow to moderate pace (for you).
  2. Choose a distance over which you will run flat out for up to 30 seconds. I use 200 metres or near enough. You could use 400 metres or even 800 metres, but you need to try to hit top pace or maximum effort and hold it for at least 20 seconds.
  3. Don’t do this cold. Try to build your heart rate to 60 % of estimated maximum (200 minus your age) in the warm up.
  4. If for some reason you don’t think you hit a maximum heart rate, do another lap flat out after a short rest.
  5. Stop and walk, note the maximum heart rate reached  in beats per minute, then take it again after one minute has elapsed. This is best done with a heart rate monitor because by the time you get your watch up to measure the heart rate, it will have slowed slightly, or a lot, depending on your fitness.
  6. Subtract your heart rate after one minute from the maximum heart rate achieved. This is your recovery number.
  7. As with all statistics of this kind, poor values are only an indicator and not a sentence, yet worth following up.

Below is the key. Patients with the lowest recovery (less than 12 beats per minute) had 4 times the risk of those in the highest category (over 40), even allowing for other factors like smoking, age, gender and hypertension.

The key (recovery in beats per minute – BPM):

POOR —> less than 12 — requires medical follow up
FAIR —> 12-20 — try to improve, follow up
GOOD —> 20-30
EXCELLENT —> 30-40
OUTSTANDING —> Over 40 — very low risk

Other tests of physical fitness are related to cardiovascular health and overall mortality. Exercise capacity is another predictor. Heart rate recovery also seems to be a reliable indicator in sub-maximal testing as well. All up, being really fit has obvious benefits beyond the walk around the block each day.

References
— Dhoble A, Lahr BD, Allison TG, Kopecky SL. Cardiopulmonary fitness and heart rate recovery as predictors of mortality in a referral population. J Am Heart Assoc. 2014 Mar 24;3(2)– Cole et al. Heart-rate recovery immediately after exercise as a predictor of mortality. New England Journal of Medicine 1999;341:1351-1357
— Cole CR, Foody JM, Blackstone EH, Lauer MS. Heart rate recovery after submaximal exercise testing as a predictor of mortality in a cardiovascularly healthy cohort. Ann Intern Med. 2000 Apr 4;132(7):552-5.
— Vivekananthan DP, Blackstone EH, Pothier CE, Lauer MS. Heart rate recovery after exercise is a predictor of mortality, independent of the angiographic severity of coronary disease. J Am Coll Cardiol. 2003 Sep 3;42(5):831-8.

Why you need to eat your greens

By PAUL ROGERS

Green leafy vegetables like spinach, lettuce, Chinese vegetables, kale and many others are part of the evolutionary heritage of primates — and humans are no exception. Eating carefully selected green leafy plants for millions of years must have made human biochemistry beautifully adapted to these foods. Too bad many of us don’t eat enough.

By Moria

They contain valuable vitamins and minerals and antioxidants including iron, lutein for the eyes and other carotenoids, magnesium for heart and muscle, folate for the heart and pregnancy, vitamin K for bones — and one nutrient that regularly gets overlooked: the plant form of omega 3 called alpha linolenic acid or ALA, which is not to be confused with the other polyunsaturated fat called linoleic acid. ALA is a shorter chain length omega 3 that the body can covert to the longer chain EPA and DHA, commonly called the ‘fish oil’ omega 3s. ALA is also found in walnuts and canola oil. It is the ‘other’ omega 3.

ALA also seems to protect us from heart disease like it’s longer-chain relations EPA and DHA. In fact, that’s how grazing animals and primates get EPA and DHA — from eating green grass and leaves and converting ALA.

What to eat, and how to prepare

I make a real effort to eat leafy greens regularly. I’ve settled on ones that I like and I try to grow them  at home as well as buy from the supermarket. I eat mainly spinach, cos lettuce, Italian parsley (not the curly leaf one), Chinese greens like bok choy, and silverbeet, called chard in some regions. I live in a sub-tropical climatic zone, so the spinach tends to be seasonal, requiring colder weather. The cos and silverbeet will grow in all except the hottest times of year, with the silverbeet being long lasting and able to be harvested by individual leaf.

For cos lettuce, you can pick the outer dark-green leaves when you need them and they just keep coming after a touch of organic fertiliser. Unfortunately, the hares also found them. Such is life.

Spinach can be eaten in salads or cooked lightly with a little olive oil, garlic, pepper and lemon juice. Like some southern Europeans, I like a large bowl, steaming hot. The silverbeet is a little stronger and works better in bakes and stir-fries for me. Parsley is more useful with the tough stems cut off, but then you can use in stir fries, salads, bowl noodles and soups or just nibble.

Fresh, dark cos with lemon juice, pepper to taste and a small amount of olive or soy oil (more ALA in soy), makes a great companion for main courses.

How greens help

Find some greens that you can eat on a regular basis and make them a regular part of your diet. If you exercise a lot you need a potent brew of natural antioxidants to assist recovery from exercise. If you’re trying to lose weight with a low-calorie diet, nutrient-rich foods are important to ensure you get your recommended daily allowance of vitamins and minerals for good health. I prefer not to juice —  and supplements are a last resort. So go greens!

The basics of longevity, anti-ageing and life extension

by PAUL ROGERS

Theories of anti-aging and life extension abound. Genes no doubt have a major role to play, and aging seems to be a programmed genetic decline that is inevitable. Yet the fundamental theory that interests us here is the idea of accumulative environmental damage to DNA, chromosomes, cells and cell reproduction over time, mostly caused by lifestyle. That is, how you live your life, day to day, and how you might arrest that process to some extent.

Much of this idea revolves around the role of reactive oxygen species (ROS) and their role in inflammation and the disease process. These ROS (free radicals) are reactive molecules created by certain life processes such as human digestion and metabolism, environmental pollution and toxic exposures including radiation, smoking, alcohol, even sunlight, and other excesses, including obesity. Antioxidant defences in the form of nutrients and antioxidant enzymes work hard to keep excessive ROS and the resulting oxidative stress under control. Although this process is fundamental to life, various excesses over time lead to damage to the mitochondria of the cell and perhaps to shortening of entities at the end of chromosomes called telomeres. This results in faulty cell division and reproduction, and thus aging.

That’s the theory of it, and there is a variety of experimental evidence in support, although the picture is not complete. Without genetic code modification, which may be possible in the near future, lifestyle change is likely to influence longevity, and certainly robustness, but only up to certain age limits.

The role of inflammation

Inflammation is the body’s attempt to suppress and heal infection and tissue injury, caused by any agent. In these circumstances, inflammation is usually self-limiting and subsides after the infection or tissue damage is adequately repaired. If tissue damage is constant, then one might expect a chronic inflammation to exist. An excess of reactive oxygen species might cause that ongoing tissue damage and thus chronic inflammation.

That seems to be predictably what occurs for many chronic disease states. Even though there are several measurable markers of inflammation, high-sensitivity C-reactive protein (hs-CRP) is the blood test that practitioners mostly turn to for a measure of inflammation. hs-CRP is often elevated in conditions like obesity, metabolic syndrome, type 2 diabetes and heart disease. CRP levels less than 1 mg/L seem to be protective of heart disease and stroke. Greater than 3 mg/L increases risk of cardiovascular disease significantly. Vigorous exercise and low body fat lower CRP. Dietary factors are still being explored, but excess weight and insufficient exercise (sorry to say it again) will almost certainly be the prime causes, and there will be a range of dietary habits within the healthy eating paradigm that provide support, or at least do not contribute substantially to inflammation.

I should say, at this point, that the idea that dietary carbohydrates, in general, are a primary cause of inflammation, as promoted on some low-carb web sites, is nothing more than quackery and can be proven so.

Calorie/kilojoule restriction

The calorie restriction or intermittent fasting idea always gets good press when a new study is released. These studies are in rodents and primates and they tend to show increased longevity with reduced energy (food) intake with adequate nutrition. This means a diet high in nutrient density and somewhat low in calories/kilojoules. This is not certain to work in humans as a general recommendation, especially considering the trouble we have with essential overeating in society. However, this process could be simulated to some extent with a regular, vigorous exercise program that would burn off that excess glucose and fat and perhaps provide a metabolic profile similar to calorie restriction. That could be one reason why physical activity, but not necessarily formal exercise, often shows up in studies of the long lived.

What you need to know about lifestyle and longevity

  1. You can enhance your prospects for a long, healthy and strong life with a few fundamental lifestyle changes.
  2. It’s not complicated, although for many people, perhaps most, it’s not easy.
  3. Eat well, exercise, don’t get fat, don’t do drugs, relax, live and work in a clean environment, and stimulate your brain.
  4. You can’t change your genes but to a degree you can change the way they’re expressed by optimising lifestyle choices.
  5. From a motivational perspective, many people seem sacrifice want they want long term for what they desire right now. It’s worth being aware of that simple psychological function of the brain in relation to your health over time. Best not to wait until you’ve had a life-altering experience of illness or accident or loss before being motivated to change behaviours.