Training for an event or maintaining fitness is always a challenge, and one which becomes even more difficult as we enter the peak season for respiratory illnesses and the flu virus.
'TIS THE SEASON
The flu season in areas like the U.S. and U.K. can begin as early as October, with December the month where it kicks into gear before reaching its peak in February. This is due to the prevalence of cold, dry air that the flu virus is better able to survive in and therefore increase the likelihood of infection.
The flu is highly contagious, with adults able to spread the virus one day prior to the onset of any symptoms and up to seven days afterward. Several other respiratory viruses also circulate during the flu season such as the rhinovirus, a cause of the "common cold".
Although anyone can get the flu, those engaging in hard training during this period are particularly susceptible.
THE 'OPEN WINDOW'
The ‘open window’ is a term used to describe the period following intense exercise when you’re most susceptible to infection, generally considered to be 3-72 hours post workout.
The theory is that although moderate levels of exercise enhance immune function, prolonged, high-intensity exercise temporarily impairs immune competence. The prevalence of this has been well-documented, with athletes routinely experiencing higher rates of upper respiratory tract infections than those who are less active.
So, how do you limit the risk of catching a nasty cold while still keeping up your training this winter?
You’d think this would be an obvious one, but eating [properly] is often over looked or under-appreciated. The depletion of glycogen (the substance deposited in tissue as a store of carbohydrates) as a result of hard training results in elevated levels of cortisol, a stress hormone that alters the immune system response.
If you have a big training session or competition coming up, consuming 30-60 g of carbs per hour offsets rises in cortisol and reduces the chances of exercise-induced immune depression.
Every cell in your body requires water, but hydration also plays a more immediate role in keeping us healthy. There are numerous defense proteins in saliva, and it plays an essential part in our immune systems first line of defense against infection.
Dehydration is the primary cause of salivary dysfunction, particularly among those 60 and older. Proper hydration with balanced electrolytes will help maintain homeostasis within the body and decrease the likelihood of infection.
Vitamin D is a fat-soluble vitamin that [like water] plays a role in almost every cell of the body, including promoting the absorption of calcium, cell growth and immune function. However, a 2016 study from the Centers for Disease Control and Prevention estimates that 14-18% of Americans have inadequate levels of Vitamin D.
Vitamin D is produced when skin is exposed to Ultraviolet B (UVB) rays from the sun, with peak hours between 10am-3pm. Moreover, studies consistently demonstrate that vitamin D status drops during the winter. For those who tend to be indoors for most of the day, a supplement throughout the winter months is generally considered safe and effective.
Comprehensive information on Vitamin D, including supplementation guidelines can be found here.
Lack of sleep weakens the immune system and has been attributed to weight-gain.
It doesn’t matter who you are, your brain and body require a minimum of 7-hours sleep each night. Many believe they can operate on less, but when tested it becomes obvious that they are not performing at their best. People just get used to feeling tired, which becomes their new normal.
The key to sleep is consistency, that means going to bed and waking up at around the same time each day – even on the weekends. If you throw this schedule off too much you may feel tired at strange hours, while your energy, appetite and mood can fluctuate.