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Staying strong during flu season

News outlets are reporting that this season’s flu infection rates are now at epidemic levels in the US and will be within the next week in the UK too. It seems a good time to highlight what you can do to best protect yourself from infection, what to do if you do get sick and what this means for your workouts.


Whilst the common cold and influenza are both forms of virus with some similar symptoms, influenza or flu is undoubtedly worse: with the likelihood of fever, body aches and exhaustion. This year it is the Influenza-A/H3N2 virus causing the most trouble, having made its way from East and Southeast Asia, through Australia and New Zealand, before arriving in Europe and North America.

Here’s an animation by the U.S. Center for Disease Control and Prevention, showing how the flu spread in a matter of weeks across the US.


Why is there a flu season?

In temperate climates, we consider winter to be the flu season, flu is indeed most common between October and May in the northern hemisphere. It is thought that the cold and dry air typical during these months help the flu virus to spread1. Conversely in tropical climates the flu infections peak during the rainy season when it is thought that the virus is assisted by the rain and humidity.

It seems that European’s immune systems are more pro-inflammatory during winter resulting in a lower threshold at which an immune response to viral infection occurs. In sub-tropical Gambia, a similar pattern is witnessed, but during the rainy season2.


Lucky you

Have you ever noticed that not everybody you know gets the flu when it is going around. This is likely down to genetics: you may be genetically set up to be resilient to a particular strain of cold or flu whilst many around you are taking to their beds. Unfortunately, this doesn’t give you a pass against all strains of cold and flu, you may pick up the next bug, whilst your best friend doesn’t.

You can’t change your genes but you can support your immune system in other ways.

Give your immune system a fighting chance this flu season

  1. Sleep well:  7-9 hours of quality sleep per night works best for most adults. The rest and repair that is only possible during sleep is essential for your immune system, as well as for in-the-gym performance and recovery from exercise.
  2. Eat well: And consider intermittent food fasting. Many find fasting for 13-16 hours out of a 24-hour period to be easy enough to do on a daily or near daily basis. Intermittent fasting may help improve regulation of inflammation, alongside other health benefits.
  3. Stay hydrated: Drink around 2 liters of water per day (this can include coffee and tea).
  4. Moderate alcohol: One or two alcoholic drinks a day may provide some health benefits. Avoid drinking more than that though as anything beyond this moderate amount will begin to have an incrementally negative impact on your immune system.
  5. Take Vitamin D: Vitamin D is known to play a role in modulating the immune system. Research suggests that reduced levels of vitamin D during winter months can increase the chances of getting colds and flus 3. Most adults should aim to get 2,000-3,000 IU of vitamin D per day from food and/or supplementation on days they are unable to synthesize vitamin D from sun exposure. Doing this will likely provide some degree of protection from upper respiratory tract infections.
  6. Optimize training frequency: Know your tolerance to intense exercise. Some individuals can thrive on 3 HIT sessions per week, some on 2 and others only 1, figure out which works for you. Beyond any initial improvement in conditioning to intense strength training, the optimal frequency for you will be genetically influenced and lifestyle stressor influenced.
  7. Be careful if using interval training: The same is true, perhaps even more so of High Intensity Interval Training. If you perform any sprint intervals in addition to your HIT strength workouts be mindful of the acute stress and therefore inflammation, this type of workout causes.
  8. Listen to your body: To follow on from above if you get to the gym feeling good enough to train but not entirely capable of your best performance, listen to your body, and hold back a little if you feel the need to. Your body fights infection for a few days before cold or flu symptoms arise. Not having as much energy as you usually do might be a sign that you are in the early stages of fighting off infection.
  9. Wash your hands: Gym equipment can harbor bugs, especially if the last person to use the equipment was infectious. To reduce your risk of picking up anything more than a loaded barbell, wash your hands with good-old regular soap after your workout. Follow the 10 second rule: 10 seconds to lather and 10 seconds to rinse off4. On a side-note, when possible avoid hand sanitizers which can kill off all bacteria- both good and bad.
  10. Moderate stress: Too much mental, emotional and physical stress drive up cortisol levels, negatively impacting your immune system. Create balance where you are able and enjoy stress relieving activities such as pleasurable social time, walking, dancing, massage, meditation, breathing exercises and qi-gong. Getting outside in nature has also been shown to help enhance immune system function.


Early warning system

As mentioned above, before you become symptomatic with either a cold or a flu your body will already be attempting to fight off the virus. During this period, it would be wise to avoid adding extra physical stress in the form of high intensity exercise. If there are no symptoms during this period, then how can you know?

The simplest way that I am aware of is via tracking of your resting heart rate. If your morning resting heart rate is 5-10 bpm, lower than normal, then your sympathetic nervous system is depressed. This is usually due to either physical exhaustion or the early stages of an infection. Either cause indicates deferring high intensity exercise and allowing the body to recover from exhaustion and/or to continue to marshal its resources to fight infection. Wait until your morning resting heart rate is back to normal before engaging in high intensity exercise. Doing so doesn’t necessarily mean you will avoid colds and flus altogether, but at the very least you won’t be digging a deeper hole for your immune system to get you out of.

During this phase of an infection it can still be beneficial to engage in stress relieving activities such as walking, massage, meditation, breathing exercises and qi-gong. Also rest more, and sleep more if you feel the need too.


You’ve definitely got it, what to do now?

If it is just a cold without fever, systemic body aches and significantly elevated heart rate then you can pretty much get on with your daily life (including the stress relieving physical activities), but don’t HIT the gym hard for a few days until your symptoms have subsided.

If you have influenza, with symptoms including fever, body aches, and an elevated resting heart rate, you are probably going to be best off in bed. Don’t even attempt to engage in moderate physical activity. Instead make sure you stay well hydrated, eat if you feel hungry (don’t if you don’t) and sleep and rest plenty. Do your best to stay positive and re-watch your favorite comedy shows and funny YouTube clips.

When you are feeling better and back on your feet again, ease yourself into physical activity. Take up to a week just engaging in moderate physical activities before you hit the weights intensely or do any form of sprint interval training.

1 responses on "Staying strong during flu season"

  1. Very informative article.

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