– Written by Carolette Snyders, Marcel Jooste, Martin Schwellnus, South Africa

INTRODUCTION

Acute infectious illnesses are a significant health threat to athletes, and can compromise training and competition. While the risk for developing these infections are perennial, certain phases during an athlete’s season may pose different risks. Recent data suggest that 80% of track and field athletes will experience an acute illness during a season, resulting in an average of 5 days of training lost per year¹. During a major event, between 6-17% of athletes will experience an acute illness, with the respiratory system most commonly affected, followed by the gastrointestinal, dermatological and urogenital systems. The majority of these illnesses were clinically diagnosed as infectious in aetiology². The burden of infections among athletes is even greater among para-athletes^3,4.

Although certain infections e.g. viral respiratory infections, may have seasonal variations, global travel for training and competing for high-level athletes increases vulnerability to infection throughout the year. Athletes are also exposed to different time zones, seasonal changes and environmental elements during international travel. Preventative measures should therefore be implemented continuously.

In the strategic planning to mitigate infection, risk factors should be identified and managed. Risk factors (Figure 1) that have been associated with infections, can be broadly categorised into training-related, nutritional, psychosocial (anxiety, stress), lifestyle (sleep, smoking, excessive alcohol), and environmental (season, climate, altitude)^5,6. The exposure to each of these risk factors varies throughout different phases of an athlete’s season. Various strategies to prevent infections can be applied to address each of these risk factors. We review specific strategies during each phase of an athlete’s season to prevent infections in track and field athletes.

GENERAL STRATEGIES TO PREVENT ACUTE INFECTIONS IN ALL ATHLETES

A transcending principle for successful prevention strategies entails effective communication and trust between athletes, medical and support staff. Without this vital component, athletes may be hesitant to follow the advice given to them or may not be willing to notify staff timeously of their ailments.

Acquiring an infection may be inevitable. Monitoring athletes for early signs of infection reduces possible health consequences. Detecting early onset of an acute infective illness can allow for the control of the spread of the infection among teams and may lead to more effective and targeted treatment. An example is the use of Oseltamivir to reduce the duration of influenza if initiated within 48 hours of the onset of symptoms⁷. Zinc supplementation has also been shown to reduce the duration of symptoms of acute respiratory infections when taken within 24 hours after the onset of symptoms⁸.

A fundamental objective should be to reduce infection transmission by limiting exposure to pathogens. Athletes as well as medical and support staff can implement practical measures to prevent infection and minimise transmission of infection by:

• Minimising physical contact with sick/ill people
• Avoiding crowded areas. Transmission of viruses will be more likely in potentially crowded places such as public transport, social gatherings and poorly ventilated confined areas⁹
• Ensure good hand hygiene by regular and thorough hand washing for >20 seconds, especially before meals and after touching potentially contaminated surfaces
• Avoid self-inoculation by touching eyes nose and mouth
• Routinely clean shared equipment and do not share drinking bottles, cutlery or towels.

GENERAL STRATEGIES TO PREVENT ACUTE INFECTIONS IN PARA-ATHLETES

In addition to general strategies for preventing infections, there are unique considerations for para-athletes. Para-athletes may need some additional assistance during daily activities or during sports participation due to the nature of their disability. An example is a visually impaired athlete who is dependent on a guide. Social distancing will not be possible should the guide, or athlete, become ill with a transmissible infection. Another example is athletes making use of non-electric wheelchairs, exposing their hands to contaminants on the wheels. Risk mitigation strategies in these circumstances are more challenging. Athletes with spinal cord injuries are also at higher risk of developing urinary tract infections (UTI’s). Strategies to prevent UTI’s among these athletes include:

• Maintaining adequate hydration with 2-3 litres per day unless contraindicated¹⁰
• Frequent bladder emptying by catheterisation with single-use catheters¹⁰
• The use of methenamine hippurate as short-term prophylaxis may also be considered, although it does not appear to be effective in persons with neurogenic bladder or kidney abnormalities¹¹
• Antibiotic prophylaxis only for those with severe or frequent UTI¹⁰
• Daily urine testing (urine dipsticks) to detect early signs of infection during high risk periods and in the few days prior to major competitions may be indicated. Importantly, athletes with spinal cord injury may have baseline bacteriuria, therefore a change detected during monitoring may necessitate early intervention and treatment.

Some para-athletes are more prone to dermatological infections. Specific attention should be given to athletes with amputations or spinal cord injuries to monitor potential pressure areas for early signs of infection.

PREVENTATIVE STRATEGIES FOR DIFFERENT PHASES DURING AN ATHLETIC SEASON

1) Pre-Season Phase

During this phase, an extensive pre-participation medical screening by the team physician for underlying medical conditions and pre-disposing factors for illness and injury, is recommended. Biomechanical, dietary and psychosocial screens are also advised for a holistic approach to athletes’ care. In this phase, appropriate vaccinations (e.g. seasonal influenza) should be considered for all athletes, coaches and support staff^7,12 and administered 5-7 weeks before possible exposure to the particular pathogen (or travel to endemic area) for adequate immune response². The timing of vaccinations for athletes is important, as some vaccines may have potential side effects, and it is advised that vaccination should occur out of completion and at least 2 weeks before competing¹³.

As mentioned previously, risk factors for infections can be divided into certain categories. These risk factors are relevant during all phases of the athletic season, but will be addressed in detail in the pre-season phase as follows:

Training-related

During this important phase of preparation, the following factors have been identified as possible risk factors of infection; an increased training load, training monotony, increased strength and speed training, participation in endurance sport⁵.

Training loads should be monitored using measurements of external and internal load. Methods of monitoring external load include training duration, or other GPS-related metrics such as distances covered, speed or pace of exercise bouts. Internal load monitoring entails rating of perceived exertion (RPE), heart rate, or heart rate variability. By monitoring training loads, coaching and support staff can manage training loads and prescribe appropriately timed rest and recovery to mitigate the risk of developing infections. This can be done by scheduling easier training after intense sessions or by scheduling a recovery/adaptation week every second or third week within the training cycle⁶.

Recommendation for training load management:

• Measure and monitor training loads
• Gradually increase training loads (intensity and volume), especially in winter months⁶
• Reduce training intensity in challenging environmental conditions such as heat, altitude, or extreme cold¹⁴
• Provide sufficient rest and recovery

Nutrition

Poor nutrition, specifically low energy availability may impair immune function. Two important goals of nutrition in the athlete are to ensure adequate energy availability, and to provide sufficient macro-and micronutrients to support immunity⁶. Periodised nutritional plans can be implemented to ensure that energy (caloric) intake matches energy expenditure, with the majority of calories comprising carbohydrate sources, especially during intense training periods⁶. There are limited data to support dietary supplementation to prevent infections in athlete. However, there is some scientific evidence to suggest that the following supplements may be of value:

• Vitamin D: Low levels of serum Vitamin D have been associated with an increased risk of respiratory infections⁵.  Dietary supplementation of 1000 IU/day has been suggested to maintain sufficient Vitamin D levels. If an athlete is Vitamin D deficient, daily dose should be adapted according to specific vitamin D levels to maintain serum 25(OH)D concentrations above 75 nmol/L (24ng/mL)¹⁵
• Probiotics: Gut colonisation commences 14 days after probiotic supplementation. Therefore, supplementation can be planned for increased periods of stress or competition. Multi-strain probiotic combinations of Lactobacillus and Bifidobacterium species (> 1 billion CFU per day) are recommended¹⁶.

Athletes and support staff, should always be conscious of the potential doping violations with the intake of dietary and nutritional supplements and ensure the products used are compliant with anti-doping regulations.

Psychosocial 

Athletes are exposed to multiple psychosocial stressors, both of internal (e.g. expectations, drive) and external (e.g. coach, financial) sources. These stressors can lead to immunosuppression and increase athletes’ susceptibility to respiratory infections. Monitoring of the mental health (mood, stress and anxiety) of the athlete using daily wellness questionnaires is important⁶. Coaches and support staff should take these psychosocial loads into consideration when prescribing training. Educating athletes on stress management and coping skills is also advised¹⁴.

Lifestyle

Medical and support staff should monitor athletes’ sleep, both quantity and quality. Sleep deprivation and ‘catch up sleep’ should be avoided as the risk of developing respiratory infections is higher among those sleeping less than 7 hours per night, with an even greater risk among those sleeping < 6 hours per night^17,18. Education on sleep hygiene should be provided and includes limiting screen-time an hour before bed⁶, limiting fluid intake to minimise sleep disturbances for restroom use, avoiding caffeinated drinks several hours before bedtime, reducing psychosocial strain and optimising bedtime routines.

Athletes should also refrain from unsafe sexual practices, excessive alcohol, smoking and recreational drug use, all associated with an increased risks of infective illness.

Environmental

Athletes may be exposed to different environmental changes e.g. weather changes, air/water pollution, or increased risk for exposure to certain pathogens endemic to a geographical area e.g. malaria. Winter months and training at an altitude above 1500 meters above sea level has been associated with an increased risk of infections⁵. Adaptation of training in challenging environments (e.g. high altitude, extreme heat/cold) are therefore advised^6,14. Athletes prone to allergy-related illnesses, should be screened and if allergens (e.g. pollen or inhalants) cannot be avoided, appropriate preventative medication is advised.

2) Travel Phase

Athletes travel across the globe to train and compete. Crossing more than five time zones can increase the risk of infection in athletes 2-3 fold¹⁹. It is therefore advised to plan sufficient time (i.e. one day for each time zone crossed)²⁰ for rest and acclimatisation before competition commences.

Travelling may also expose athletes to different climates, altitude as well as possible pollutants and endemic diseases. It is important for the medical team to obtain information from a reliable source (e.g. CDC or WHO website) on the final destination regarding possible endemic diseases, including infections with insect vectors (e.g. mosquitoes, flies, ticks). This will allow for appropriate and timely vaccination and chemoprophylaxis if relevant.

Travel preparations

The travelling physician should enquire about the medical needs of both the athletes and support staff before departure in order to prepare appropriately, including what medication to take with, infection mitigation strategies, etc.

Additional travel preparations should include:

• Providing adequate and timely education to all athletes and team members on infection prevention measures and the immediate response plan for infections during travel¹²
• Packing of insect repellents, mosquito nets for beds and chemoprophylaxis (if appropriate) to minimise risk of insect borne infection
• Athletes prone to infection/high risk athletes should preferably occupy a single room
• Book an extra room to serve as an isolation area for ill team members²⁰
• Attempt to synchronise meals and sleep/wake cycles few days before departure in order to minimise sleep disturbance and jet lag at the destination²⁰

During travel

During travel, it is important for athletes and the support team to:

• Wear face masks to minimise exposure to air-borne pathogens
• Avoid touching areas potentially contaminated by pathogens at the airport (e.g. check-in counters, trays at the security gate screening, water fountain taps) and on the aeroplane (e.g. chair headrests, air vents, tray table and lavatory handles²¹. Sanitise or wash hands immediately after touching these objects.
• Disinfect high-risk surfaces where seated with alcohol-based sanitisers or antibacterial sprays or wipes⁷.

At destination

The travel destination may differ vastly from the athlete’s country of origin with regards to food types, water and environmental factors. It is advised that all team members should:

• Avoid the risk of travellers’ diarrhoea by regular hand washing, drinking only bottled water, avoid eating raw fruit and vegetables and eating only freshly prepared and thoroughly cooked, hot food²²
• Optimise sleep hygiene and minimise sleep disturbances e.g. eye masks, ear plugs and comfort (e.g. own pillow) to maintain robust immunity
• Ensure optimal cleaning at the accommodation including the kitchen, living and dining areas in order to prevent the spread of contagious infections¹²

3)  Competition Phase

Implementation of all the general infection prevention tips are important throughout all phases. In the high-pressure environment of competition time, even more care should be taken to prevent infection, due to its potential negative impact on athletic performance.

During competition time, special attention should be given to:

• Daily monitoring for early symptoms and signs of infection
• Increase personal hygiene e.g. regular hand washing, disinfectant gel/liquid use
• Avoiding close contact with other individuals e.g. handshakes, hugs, media interviews etc.
• Use of face masks in confined and crowded spaces, e.g. transport, poorly ventilated indoor areas
• Optimise ventilation in living spaces and transport
• Minimise additional life stressors
• Optimising sleep and nutrition
• Well planned action plan on the identification, isolation and management of ill athletes and/or support staff

CONCLUSION

Acute infections are a significant threat to athlete health and performance, including track and field athletes. Implementing effective prevention and early management strategies are key to optimising athletes’ performance and limiting time-loss from training, and competition.

This article summarises key aspects for consideration during specific phases of a track and field athlete’s season. Sports physicians, medical, coaching and other support staff can develop and implement their own preventative strategies, according to the risk factors of their athletes. We propose tailoring these strategies according to the different phases of the athlete’s season. The effectiveness and applicability of these strategies should be systematically monitored and modified according to specific needs and feasibility.

Carolette Snyders M.B.Ch.B., Ph.D.¹

Sports Medicine

Marcel Jooste M.B.Ch.B., M.Sc.¹

Sports Medicine

Martin Schwellnus M.B.B.Ch., M.Sc.(Med), M.D., FACSM^1,2

1               Sport, Exercise Medicine and Lifestyle Institute (SEMLI)

Faculty of Health Sciences,

University of Pretoria

Pretoria, South Africa

2              International Olympic Committee (IOC)

Research Centre of South Africa

Contact: carolette.cloete@semli.co.za

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Header image by Andrea Piacquadio (Cropped)