World Triathlon Coaching and Training Guidelines for the COVID-19 pandemic period

4. Coaching implications of the COVID-19 period

4.4. How to keep the immune system healthy?

The importance of exercising

Regular exercising is proven to have multiple positive effects on health:

  • improves sleep quality;
  • reduces stress;
  • facilitates cognitive functions;
  • has positive effect on mood and attitude;
  • helps to control body weight.

Aerobic exercises activate the cardiovascular system and according to research have a major role in preventing heart diseases, hypertension and diabetes.

Strength training mainly engages the musco-sceletal system, which provides form, support, stability, and movement to the body. Stronger muscles also mean better mobility and balance, and thus a lower risk of injury.

Shorter, stiffer muscle fibres make the body vulnerable to injuries, back pain, and stress. Post-workout stretching exercises that isolate and stretch the elastic fibres surrounding muscles and tendons can counteract this. In addition, stretching improves posture and balance.

Physical exercise has numerous effects on the human body, including the immune system. After strenuous exercise, athletes pass through a period of impaired immune resistance. During this period, athletes are theoretically more susceptible to upper respiratory tract infections, although a causal relation has never been demonstrated. Moderate exercise seems to have a beneficial effect on the immune function, which could protect against upper respiratory tract infections. Exercise has effects on both the humoral and the cellular immune system.

Rest and recovery considerations

Physical exercises are stresses applied to the body. To get fitter the body needs to be allowed time to rest and recover after exercising. During this rest and recovery, the body overcompensates and strengthens itself, so that it is better able to cope with being asked to undertake the same activity again. After a sufficient period of rest, the body has adapted and has achieved a higher level of fitness. This also means improved functionality or “fitness” of the immune system.

Diagram of a person in the middle, with 8 circles around them and arrows from these pointing into the person, these circles contain the following items: Environment, Training and racing, Nutrition, Lifestyle, Travel, Recovery activities, Mental state, Equipment

Figure 6 – Source: ITU Triathlon Coaching (Level 1 and Level 2 combined)

In the period of COVID-19 coaches should not only be careful with the training loads but must enable the necessary time for rest and recovery bearing in mind that factors that have effect on recovery (such as environment, lifestyle, stress factors, nutrition, etc.) might have changed. Make sure to choose recovery times in line with the training load that has been applied!

Zone - Training TypeTime (Hours)
Zone 1: Regeneration Aerobics to accelerate recovery
Zone 2: LT-1 Extensive Aerobics 6-12
Zone 3: Intensive Aerobics 12-48
Zone 4: LT-2 "Threshold" 48-100
Zone 5: VO2max 36-72
Zone 6: Anaerobic Capacity 12-24
Zone 6: Lactate Tolerance 48-72
Zone6: Max Strength 24-48

Table 1 - Source: ITU Triathlon Coaching (Level 1 and Level 2 combined)

Nutritional considerations

Eating healthy is also of key importance in this exceptional situation. A balanced diet of natural food can deliver everything that an athlete needs, but special attention needs to be paid to proper vitamin intake. There are many recommendations for a balanced diet, and this can vary for individuals and different genetic and cultural backgrounds. A healthy diet should be:

  • Complete – contains all nutrients, across a daily diet, so food items from each Macronutrient group are consumed and a balance across micronutrients is also maintained. The closer to their natural state a food is the more of the nutrients it retains, an apple is significantly more nutritious than apple juice. Therefore, target whole foods where possible.
  • Balance Nutrients – for adults a ratio of 60-65% carbohydrates, 10-15% protein and approximately 25% 'healthy' fats would be a sensible starting position for a diet. Children need slightly more protein in their diet.
  • Safe – ensure food is free of contamination or infectious disease, such as Salmonella.
  • Enough – sufficient to cover needs for energy and growth and repair.
  • Suitable – according to tastes and culture of those consuming food and adjusted to their economic resources and availability. In many locations the COVID-19 pandemic brought exploding demands towards basic goods, including food products. We all might face shortages and products that cannot be sourced making it challenging to put together a healthy plate, but it is still important to keep in mind the basic nutritional considerations.

 Image of the eatwell plate

Image Source: Crown Copyright-Public Health England in association with the Welsh government, the Scottish government and the Food Standards Agency in Northern Ireland.

  • The secret to better health — exercise, Harvard Health Publishing
  • The effects of physical exercise on the immune system, Jeurissen A., Bossuyt X., Ceuppens JL., Hespel P., Ned Tijdschr Geneeskd. 2003 Jul 12;147(28):1347-51.
  • ITU Triathlon Coaching (Level 1 and Level 2 combined), Principles of Conditioning (L1c), Recovery
  • ITU Triathlon Coaching (Level 1 and Level 2 combined), Measuring Fitness (L1c), Recovery
  • Based on: ITU Triathlon Coaching (Level 1 and Level 2 combined), Sport Science, Nutrition (L1a)