Beating the Colds and Flu...

Hi all...

These two atricles were posted on the SA Rowing Coaches' Association website recently. Please read them (I know it sounds alot like school work)... You all know what contributes to you getting sick and I think we all need to start making sure that we're doing everything we can to stay healthy and able to train.

Matt

Keeping the Bugs at Bay during the Winter Season

Dr David Nieman

From Coaching Australia. Vol. 9. No 1. August 2005

The relationship between exercise and the immune system is of great importance for coaches and their athletes during the winter season, when illness and infection can compromise an athlete in training and competition.

The ‘Open Window’ Theory

It has been suggested that bouts of heavy, prolonged exercise can lead to a temporary but clinically significant reduction in an athlete’s immune function. During this so-called ‘open window’ of altered immunity, which may last between three and 72 hours depending on the immune measure, viruses and bacteria may be able to gain a foothold, increasing the risk of infection. Parts of the immune system that may change after prolonged, heavy exertion include:

• decrease in natural killer-cell activity — the ability to kill infected cells or cancer cells decrease in nasal and salivary Immunoglobulin A concentration — an antibody that combines with protein in saliva and tears to defend the body from invading germs


• high blood levels of the hormone cortisol cause high blood levels of neutrophils and low levels of lymphocytes — two different types of white blood cells


• decrease in nasal mucociliary clearance — sweeping movement of small hair-like structures in the nose


• increase in plasma concentrations of pro and anti-inflammatory immune cells known as cytokines.

Taken together, these changes suggest that the immune system is temporarily suppressed and stressed following prolonged endurance exercise. It has been suggested that the immune system reacts to the inflammation caused by heavy exertion, diverting resources that normally protect against infection, particularly upper respiratory tract infection.

Thus it makes sense, but still remains unproven, that upper respiratory tract infection risk is probably increased when an athlete goes through repeated cycles of heavy exertion, has been exposed to viruses and bacteria that cause infections, and has experienced other stressors to the immune system, including lack of sleep, severe mental stress, poor nutrition or weight loss.

Role of Nutritional Supplements in Reducing Exercise-Induced Changes in Immunity

Although endurance athletes may be at increased risk of upper respiratory tract infections during heavy training cycles, they still need to exercise intensively to compete successfully. Therefore, one solution could be taking nutrient supplements that have the potential to boost immune function. The influence of carbohydrate, vitamin C and glutamine on the immune response to intense and prolonged exercise has been investigated with varying results.

Carbohydrate

The most impressive results have been reported in carbohydrate supplementation studies. Research has established that blood glucose concentrations are linked to the body’s hormonal system, including the stress hormones. This, in turn, is linked to the body’s immune system. By keeping the blood glucose levels up, stress hormones are reduced and immune system function is better maintained than when just water is ingested.

Research shows that athletes ingesting carbohydrate beverages before, during and after prolonged and intensive exercise should experience lowered physiologic stress.

This model suggests that carbohydrate supplementation during prolonged and intensive exercise maintains or elevates blood glucose concentrations, reduces the normal rise in stress hormones, and thereby counters negative immune changes.

Vitamin C

Several studies of South African ultra-marathon runners have shown a link between vitamin C supplementation (about 600 mg/day for three weeks) and fewer reports of upper respiratory tract infection. While findings suggest that vitamin C supplementation may be beneficial during and after strenuous physical activity, the data does not prove that supplementation with vitamin C is also beneficial during moderate training.

Glutamine

Glutamine, a non-essential amino acid (building block of protein), has attracted much attention from investigators.

Lower levels of glutamine result in reduced immune function, and reduced blood glutamine levels have been observed after prolonged exercise. It has been suggested that glutamine supplementation may overcome the problems of overtraining, or the impaired immune function suffered by athletes involved in heavy training. However, most studies have not favoured such a relationship.

Summary

There is growing evidence that prolonged intensive exercise is associated with reduced immune function and an increased susceptibility to opportunistic infections, particularly upper respiratory tract infections. Exercise-induced increases in stress hormones may be responsible. Attempts have been made to prevent these negative changes through nutritional means, with carbohydrate supplementation via a sports drink offering the most promising results so far.

Coping With Colds
By Paul Davies & Dr R Budgett
October '98

Common autumn and winter illnesses can generally be split into two groups; those that only affect the lining of the nose and throat (colds and upper respiratory tract infections (URTIs)), and more serious infections where the virus or bacteria cause more widespread symptoms. The symptoms for colds and URTIs are generally localised to above the neck and include dry sore throat, nasal congestion and/or runny nose, sneezing and slightly swollen glands. If, in addition to the above symptoms, there is a significant rise in resting heart rate (greater than 20%), significantly swollen glands, cough, general aches, fever and fatigue then a more serious infection is likely to be present.

For colds and URTIs localised to above the neck, light exercise will help to speed recovery. This should be performed at a very low intensity (lower than UT2) for between five and seven days, until the symptoms have disappeared. It is important that only light exercise is performed at this time. This could take the form of cross-training such as walking or very light cycling. If hard exercise is performed whilst symptoms are still present, there is a significant risk of delayed recovery and of secondary infection such as sinusitis or bronchitis. If the symptoms are no longer present following 5-7 days of easy exercise, then training can be gradually increased over a period of three days, with normal training being resumed between the eighth and tenth day.

In the presence of symptoms below the neck that suggest a more severe and widespread infection, a medical opinion should be sought and complete rest for between three and seven days must be taken. Most of these infections are caused by viruses and will not benefit from antibiotics, but occasionally there is a secondary bacterial infection and antibiotics may be given. When symptoms have reduced, such that aches, fever, fatigue and productive cough are no longer present, light exercise can be performed. This should be done for a further five to seven days, until all symptoms have disappeared. This can then be followed by an escalation of training up to normal levels over three days. A cough may persist for up to three weeks after a chest infection and very intensive exercise should be avoided until this resolves.

It is important to note that during the early stages of any infection, extra rest and regeneration strategies, as well as light exercise will help to speed recovery. This means drinking large volumes of fluid (> 40 ml of fluid per kilogram of bodyweight per day), eating a healthy diet, using relaxation techniques and increasing ‘lifestyle rest’ to help maximise recovery. Taking paracetamol or aspirin will help to alleviate symptoms but unfortunately will not speed recovery. You are most infectious at the start of a cold, so to avoid spreading the illness it may be prudent to avoid other members of the team during this time.

G., Ilback N. G. (1992), Exercise and infection: interaction, risks and benefits. Scand J Med Sci Sports. 2. 177-189.