Exercise when Sick: Stop? Go? How to Reduce Risks?

Is it OK to exercise when sick? What symptoms should keep someone off the playing field?

When trying to decide if an athlete is too ill to participate in sports, I tend to ask the following questions:

• Is the athlete currently too ill to exercise?
• Will exercise make the athlete at-risk for more serious or longer-lasting illness?
• Is the athlete contagious to other members of the team or sport group?                                

Study and experience tells us that a fever over 100.4 degrees Fahrenheit may increase metabolic demands of the body, often making exercise more difficult. Thus, many authorities recommend starting with lighter levels of exercise with a fever, and using overall performance to advancing to higher intensity of exercise. Some athletes may perform quite adequately with a fever, while others will need complete rest from exercise until the fever is gone for at least 24 hours.

I have found that the neck rule can also assist athletes and parents in deciding on sport participation, with or without a fever:

• If symptoms are entirely above the neck (runny nose, sore throat, mild headache, etc) then there is less potential risk for more serious illness with exercise. Recommend light exercise at first, and if symptoms do not worsen, then gradually increasing the intensity of the exercise.
• If symptoms are below the neck (productive cough with mucous, chest pain/tightness, stomach ache, vomiting/diarrhea, rash, muscle/body aches) then there is a greater risk not only for worsening individual symptoms, but also for spread to teammates. Thus, recommend no activity until these symptoms are gone for 24 hours. If there is any concern contact your medical provider to receive further evaluation.

How can we limit spread of colds and other illnesses during the winter months?

Multiple factors contribute to healthy function of the immune system in preventing illness

No athlete wants to be sick during the season and no athlete wants to spread illness to other team members. Following some basic rules can help prevent the spread of infections: 

• Do not share water bottles, cups, towels, washcloths, or tissues.
• Shower immediately after exercise and change into clean clothes.
• Launder athletic equipment on a regular basis.
• If prescribed medications- take them as directed for the full length of the prescription.
• Use antibiotics only for the intended illness; never use them for a new illness or when they were not specifically prescribed. Incomplete or improper use of antibiotics can lead to bacterial resistance that may increase both the spread and severity of an illness.
• Get adequate sleep and nutrition as fatigue and poor diets can weaken the immune system.  Get no fewer than 8 hours of sleep a night, and schedule at least one rest day from exercise per week. Low-fat diets (less than 10-15% of daily calories as fat) and less than 4-5 fruits/vegetables per day can also reduce ability to fight infection.
• Consider the Influenza Vaccine (flu shot) in the fall months.  Influenza A/B viruses are common sources of illness and disability during the winter months and flu shots can reduce both individual and team risks from flu symptoms.

How does the amount of exercise influence risk of getting sick?

Moreira A et al. Br Med Bull 2009;90:111-131, © The Author 2009. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org

The above figure demonstrates that both intensity of exercise and fitness level can influence the risk of upper respiratory infection. More moderate levels of exercise can be protective against illness, while lower levels and higher levels of exercise may actually be related to an increased risk. This is often why athletes get sick right after higher level competitions or at the end of a particular sport season. Higher levels of fitness may also be protective against respiratory illnesses.

Peak Athletic Performance Often Leads to Peak Illness Risk

It can be an awesome feeling to be "in the zone" or "performing better than I have in years”.

It however, can be a major downer when that peak performance comes at a cost to immediate health and the immune system. 

Anyone who has been around the time of a big show knows how performers like to celebrate afterward. That's right- everyone tends to get sick.

Exchange the big show for the big race or big competition and you often see the same outcome- many athletes go from the podium or finish line to the sick bed. Saw it at the Olympics where my first up close and personal views of gold, silver and bronze medals were around the necks of athletes coming in to the medical unit for upper respiratory infection evaluations. 

Those were the fortunate ones who had timed their peak performance to occur at the Games and didn't have unplanned illness interrupt training or competition.

Unfortunately, many times this fairly tale ending doesn't occur. Peak performance earlier in a season leads to mid-season illness and eventual disappointment. Solid evidence tells us that moderate levels of physical exertion are protective against illness, while higher extremes of activity can diminish immune defenses and increase illness risk. Having a solid base of fitness before assuming more rigorous training can also reduce risk of diminished immunity and increased chance of illness.

It is nearly impossible to maintain peak performance for too long, especially over a schedule of multiple events combined with the stressors of school, homework, and a social life. 

Trying to get adequate sleep (minimum 8 hours a night), proper nutrition including berries, cherries, and fish for the anti-inflammatory effect, and planned off days from training and competition can help combat the stressors that sap performance.

More important is adhering to the principles of periodization, where well-constructed training blocks are created to allow peaking at optimal times while also maintaining periods of relative rest and recovery.

So, if an athlete tells me "I'm at my best" right before a chosen high level competition, then less cause for concern. Still might get sick afterward, but the merging of preparation and schedule hopefully is fairly favorable.

If an athlete is peaking well before that big competition which is still weeks or months away or with many of my young athletes when they have to get up every week because "every game is a big game", then my worry starts to go up.

Nothing worse than showing up in the doctor's office missing key training days or even worse, important competition time due to illness. Enhancing the immune system with proper rest and recovery can lead to more visits in the winner's circle and less time scheduling visits with the medical staff.