A study by US researchers from the University of North Carolina found that in a group of over a thousand, those who exercised regularly were much less likely to experience symptoms of respiratory illness including coughing, sneezing and fever, and if they did, the symptoms were up to 32% less severe than those who didn’t exercise!
What’s even more interesting is an experiment published in the journal Brain, Behaviour and Immunity; researchers from the University of Illinois tested 3 groups of mice that were infected with flu. The first group rested. The second group ran for a leisurely 20-30 minutes. The third group ran for a taxing two and a half hours! Each group then repeated this regime for 3 days, until they began to show symptoms of flu. In the first group of mice who rested, more than half of the mice died from the flu. In the second group of mice who ran leisurely each day, only 12% died from the flu. In the third group of mice who ran vigorously each day, 70% of them died!
Insights here?
Regular moderate exercise may help to boost your immunity against cold and flu!
Why is this happening?
Well, there’s a ‘J-curve’ theory coined by physiologists when it comes to exercise and immunity. According to this theory, the risk of catching a cold or flu and the risk of having severe symptoms if you catch a cold or flu drops if you regularly take part in moderate exercise. However, the same risks increase sharply if you regularly undertake intense exercise or exercise for a long period of time.
Scientists are endeavouring to uncover the reason behind this phenomenon.
Some studies have shown that exercise promotes better circulation, allowing immune cells and substances to travel more efficiently through your body to do their job. This also means that any signs of disease or illness in the body can be detected and dealt with at an even faster rate. This could explain why moderate exercise help to boost immunity.
Other studies looked into the relationship between T1 immune cells (causes inflammation to ‘burn’ off invading viruses) and T2-helper cells (causes anti-inflammation to put out the fires T1 cells started). Too much T1 response means we, and the virus, get ‘burnt’. Too little T1 response, or if T1 gets put out by T2 too soon, then the virus doesn’t get ‘burnt off’.
Researchers concluded that moderate exercise increased the shift of an immune response from T1 to T2 by just the right amount to strengthen the body’s immune response against the flu. On the other hand, intense exercises prolonged immunosuppression, which caused T1 response to finish prematurely, before the defence had finished its job.
So what is a moderate level of exercise?
Well, this varies from person to person. If you have a heart-rate monitor, your moderate intensity should have your heart rate at 70-80% of your maximum heart rate during exercise.
If you don’t have a heart rate monitor, then you can gauge the intensity by how easily you could talk during exercise. If you find it challenging but still able to utter a few words, then you’re at your moderate intensity. If you find it impossible to utter anything, then that’s high intensity.
The Australia Department of Health recommends 150-300 minutes of moderate intensity exercise weekly for optimal health. As health and a healthy immune system are intricately linked, we should all aim for 300 minutes each week!
Are you getting your dose of immunity against cold and flu?
Remember, “Your body is always worth fighting for” – Lesley Kinzel
