Winter is a time when we’re more susceptible to bugs and illnesses. And there’s nothing more frustrating for athletes than missing training due to a cold or flu. Here’s how to fend off this season’s colds by getting your defenses into top gear.
The irony is that, while regular exercise boosts your immune system, intense training can have the opposite effect and depress immune cell functions. Such changes create an ‘open window’ of decreased protection, during which viruses and bacteria can gain a foothold, increasing the risk of developing an infection. It is thought that the increased levels of stress hormones, such as adrenaline and cortisol, associated with intense exercise, inhibit the immune system. Other factors such as stress, lack of sleep and poor nutrition can also depress immunity.
Restricting your calorie intake during periods of hard training can increase cortisol levels and result in a loss of immune function, making you more prone to infections. Match your calorie intake and expenditure.
Feed your immune system well
Deficiencies of protein and certain nutrients can weaken your immune system. Ensure you’re consuming plenty of foods rich in immunity-boosting nutrients – vitamins A, C and E, vitamin B6, zinc, iron and magnesium. Focus on fresh fruit, vegetables, whole grains, lean proteins, beans, lentils, nuts and seeds, while limiting highly-processed foods.
Carb up before, during and after hard workouts
Long or intense training coupled with low glycogen stores is associated with bigger increases in stress hormones and greater suppression of your immune cells. If you’re doing a high-intensity workout lasting longer than 60 minutes, take in 30–60 g carbohydrate per hour. This can reduce stress hormone levels and the associated drop in immunity following exercise.
Drink plenty of fluid
This increases your saliva production, which contains antibacterial proteins that can fight off airborne germs.
Get enough sleep
Sleep is when the body and immune system recovers . During sleep your body produces antibodies and cytokines, proteins that co-ordinate your body’s response to infection and inflammation. Lack of sleep depresses the immune system, making you more susceptible to illnesses and infection. One study found that getting fewer than 6 hours sleep a night can quadruple your risk of catching a cold. Aim for 7 to 9 hours each night.
Be supplement savvy
In general, there is not much convincing evidence that supplements boost immunity or prevent colds in healthy people. Moderate doses of vitamin C supplements (<1g) may help reduce the incidence of colds during periods of severe physical stress, such as during heavy training blocks or before and after competition, according to a Cochrane review of 29 studies, but not in non-athletes. There’s also some evidence that probiotic supplements may help protect against and reduce symptoms of upper respiratory tract infections.
A better way to increase the beneficial micro-organisms in your gut, though, is to eat a varied diet rich in fibre, aiming for around 20 – 30 different fruit, vegetables, whole grains and pulses a week. Including fermented foods containing probiotics, such as live yogurt, sourdough bread, sauerkraut and kefir will also help. As will eating prebiotic foods (e.g. onion, garlic, lentils, beans, asparagus and leeks) .
But, if a cold has already taken hold, try sucking zinc acetate lozenges regularly throughout the day (equivalent to a daily dose of at least 75mg elemental zinc). They have been shown to reduce the duration of the common cold by 44%. It’s important you take zinc in lozenge form (not tablets) as it needs to dissolve in the mouth and act directly on the cells lining the pharynx. I’ve used Healthspan zinc defence lozenges with success (I am not sponsored or paid by the company!). However, there is no evidence for taking zinc tablets.
If you enjoyed this post and want to find out more about sports nutrition, then check out the new edition of The Complete Guide to Sports Nutrition , the definitive practical handbook for anyone wanting a performance advantage. It’s the 8th edition (the 1st edition came out in 1993!) and it has been fully updated and revised to bring together the latest research and information on sport and exercise nutrition. It covers topics such as
- Maximizing endurance, strength and performance
- Carbohydrate, protein and fat requirements
- Sports supplements
- Improving body composition
- Eating plans to cut body fat, gain muscle and prepare for competition
- Hydration and fluid intake