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How to boost your immune system to stay healthy

by Dr. Reaburn talks about his latest book

Most serious athletes young and old get sick at some stage. The sore throat or illness may be due to training too hard and / or too long and / or too often, hanging around people with illness, not eating well, or not easing up on training when the stress of life (work, relationships, travel etc) builds up. While planning your training program smartly to have hard-easy days and weeks, having one day of rest a week, and easing back on training when under pressure helps prevent illness or overtraining happening, research has shown that there are plenty of nutritional strategies that can help us too. These include adequate hydration, the right number of calories/kilojoules, adequate amounts of carbohydrates, fat and protein, timing the intake of the carbs and protein, and some supplements.

Serious masters athletes who train for speed and power, strength or endurance, are always trying to maximise their training performance. Research has shown us that there is “J-Curve” of exercise-related immunitythat says if we do too much exhaustive exercise, our susceptibility to infection increases dramatically.

Smart older athletes train consistently, follow quality sessions with easier ones, stick to a training program that progressively builds quality and quantity of training, listen to their bodies, and use the recovery strategies that science has shown work. There is an increasing body of science that is showing that nutrition can play a major role in building up the immune system to prevent getting ill when training.

Below I’ve summarized the practical implications of what the research says:

1. Hydrate well and consistently: Monitoring body weight before and after quality training is a must as is monitoring the colour of your pee. Athletes need to replenish a litre of fluid for every kilogram of weight lost (20-24 ounces for every pound for our American friends). Urine colour should be clear to light yellow.

2. Consume adequate daily energy: The diet should consist of adequate calories (kilojoules) obtained from carbohydrates and protein. These sources include natural cereals, grains, fruit and vegetables and low-fat meats. My Bookhas a major section in the nutrition chapter devoted to calculating your daily energy expenditure using a variety of equations based on age, gender and training quality and quantity.

3. Vitamin and minerals should be obtained naturally from a well-balanced healthy diet focused on natural ingredients and mixing the colours of these food sources. To cover my butt on these, I take a multivitamin-mineral supplement daily that has an emphasis on vitamin B and includes iron, zinc and calcium – all of which are needed by older endurance athletes.

4. Consume adequate protein: Daily protein requirements are suggested to be 1.2 – 2.0 grams / kg body weight / day for athletes. Recent research suggests older athletes that train had and / or often may require amounts at the top of this range. Moreover, recent research suggests strength and power athletes should consume a nutrient mix of 2 (carbohydrate) : 1 (protein), endurance athletes a 4 : 1 ratio and team sport athletes a 3 : 1 ratio with the protein dose 0.25 – 0.50 grams / kg body weight consumed every 1 -2 hours after the workout for six hours. This link shows the typical protein contentof foods.

5. Carbohydrate intake should be between 6 and 10 gm / kg body weight per day. The harder or longer the athlete trains, the higher the amount needed. Up to 60% of the daily energy expenditure should be in the form of carbohydrate. This link is an excellent site showing the carbohydrate content of common foods.
My book The Masters Athlete has an excellent chapter on nutrition for the older athlete. It is an adaptation of the chapter I have written for the last three editions of the book “Clinical Sports Nutrition” (2009) used by dietitians throughout the world.

6. Carbohydrate intake prior, during and after training at levels an individual athlete can cope with. Liquids such as sports drinks that are a 6-8% (6-8 gm / 100ml – look at the ingredients table on the back of the bottle) carbohydrate solution should be taken every 15 minutes during training sessions longer than an hour to aid recovery and reduce muscle inflammation. After training, a carb intake of 1.5 gm / kg body weight immediately or 0.6 – 1.0 gm / kg within the first thirty minutes and again every 2 hours for up to 6 hours maximizes replacing the muscle and liver carbohydrate stores ready for the next session.

7. Fat should be 20-25% of daily energy intake. A minimum of two servings (8 ounces) of fatty fish (salmon, trout, sardines, herring) per week is recommended as the poly-unsaturated fatty acids in these fish have been shown to optimise the immune system.

8. Flavonoids such as those found in tea and berry products may benefit the immune system. Quercetin, found in the skins of apples and red onions is a powerful antioxidant and anti-inflammatory that has been linked to prostate cancer prevention and been shown to reduce the incidence of upper respiratory tract infections.