A Triathlete’s Guide to Cold and Flu Season

Find out how you can train and stay healthy through cold and flu season by making just a few lifestyle tweaks to manage stress.

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‘Tis the season for the flu, winter colds, and other upper respiratory infections (URI) that put a damper on our workouts and threaten our fitness. It is well-reported that during periods of heavy training and racing, athletes are more susceptible to, and may experience, an increase in URI. A “window of altered immunity” following prolonged or heavy exertion exists (that may last between three and 72 hours), wherein many components of the immune system exhibit change. This window is an opportunity for viruses and bacteria to gain a foothold. In addition, factors such as travel, low energy availability, and high levels of stress and anxiety also put athletes at risk. So, what can we do from a nutritional, training, and lifestyle standpoint to combat getting sick? Read on for some recommendations to maintain immune health and keep running strong during cold and flu season!


There are several nutritional strategies that you can follow to improve your immunity as an athlete. These include a handful of key supplements. Those that have strong support in the literature are vitamin D3, probiotics, vitamin C, and zinc lozenges.

  • Consider taking 1000 IU/day of vitamin D3, from fall to spring, to avoid insufficiency.
  • Consider probiotics (>1010 live bacteria/day) if you are illness prone or while traveling.
  • At the onset of a cold, take zinc acetate lozenges (75 mg/day) to reduce the duration of symptoms – must be taken < 24 hours after onset.
  • Also consider 0.25-1 gram/day of vitamin C to decrease URI incidence, as well as reducing URI duration, if initiated after the onset of symptoms.
  • In addition to supplementation, there are also several general nutrition strategies to support a healthy and strong immune system:
  • Eat a well-balanced diet with a focus on fruit and vegetable consumption (5-7 servings/day) to provide adequate nutrient density.
  • Consume > 50% of daily energy intake as carbohydrate.
  • Consume an adequate amount of protein (1.2-1.6 g/kg/day).


Managing overall stress also plays a large part in immune health. Some training principles to abide by, that will ultimately keep you healthy, both, from injuries and from URI include:

  • Following a proper periodized training program that allows for a recovery week after every two- to four-week build period.
  • Keeping volume and intensity increases limited to 5-10 percent per week (maximum), especially during the winter months.
  • Schedule recovery days (and ensure that these days are truly EASY—heart rate training is good for this!) following high-intensity sessions/days.


And finally, managing overall stress and following some simple principles, with regards to travel and sleep, can also hugely impact your body’s immunity. It is a well-known and understood concept that psychological stress has a large influence on immunity and resistance to infection.

  • Aim for > 7 hours of sleep each night. You cannot “catch-up” to multiple bouts of restricted sleep; consistency with sleep is king. If possible, daytime naps can be beneficial!
  • Although easier said than done, keeping life/psychological stress to a minimum can also play a big role in staying healthy. This may mean reducing training stress during periods of high life-stress or travel, to manage your overall stress-load.
  • Avoid sick people! It sounds simple, and it is.  When exposed to those with URI’s, do not underestimate the importance of thoroughly washing your hands in order to avoid self-inoculation by touching your eyes, nose, and/or mouth.
  • Do not train with below the neck symptoms.

It is possible to remain healthy and training strong throughout these tough winter months. A focus on nutrition, sound training principles/planning, and overall stress-management can be a great start towards fortifying your immunity and overall well-being!

This article originally appeared on Trainingpeaks.com.

Beth Peterson RD, CSSD, LDN is a Registered Dietitian and Board Certified Specialist in Sports Dietetics.

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