For healthy individuals, running offers many benefits. Said Dr Derek Li Shi An, 34, a family physician, “Running improves bone health and cardiovascular fitness, to put it simply. These have knock on effects and preventing things like osteoporosis, high cholesterol, hypertension and diabetes.”

Dr Derek Li (Credit: MarathonFoto)

Avoid strenuous exercises when you are ill

But when you are sick, it might be best not to run though. Said Dr Li, “In general, it is better to avoid strenuous exercise when you are ill with any condition. With a cold in particular, I would recommend stopping exercise completely if there is any fever, or chest symptoms like phlegmy cough, breathlessness or wheezing. In such instances, your lung function may be compromised and can make running or any other exercise dangerous. Fever also dehydrates the body and makes any exercise more risky with respect to heat injuries. You could collapse permanently, if you exercise with a fever.”

With a cold, there could also be other implications if you continue to run. Said the doctor, “Running puts stress on your heart and lungs. If you have a cold, that makes it extra taxing to run. Yes, running with a cold can make the cold worse, as the infection could in theory, more easily spread to the lungs and cause a lung infection.”

Running offers many benefits to healthy individuals, but Dr Li does not recommend running when you are ill.

The doctor added “But doing light exercise should be ok though if you just have runny nose with a slight cough. I recommend only lower intensity runs and possibly for a shorter duration as well; this minimises the chances of the symptoms worsening.”

Pay attention to how you feel

Dr Li stresses that you should pay attention to how you feel, in order for you to decide if you should run that day. He said, “If you are unsure about the severity of your illness, it is best to see a doctor to get a proper evaluation. The severity of an illness often has little correlation to its duration or onset. Some bugs take a week or more to get serious but some are serious from Day One. It is best to pay attention to how you feel. If your energy levels are low, skip the exercise. This applies to times when you are not ill as well; there is no fitness benefit from trudging through a run just for its own sake.”

He added, “Once your energy levels are back up, it is ok to resume exercise, but it is always best to start with light exercise for a day or two, before working back to your usual exercise intensity.”

Running in the rain does not make a person get sick

Running in wet weather does not make a person fall sick.

On running in the rain, Dr Li does not think it can make a person get sick, though some may think that this is the case. He said, “I don’t believe that it is possible to get sick from running in the rain in Singapore. Our weather is warm and humid enough that even with rain and strong winds, it is still significantly warmer than running in cooler countries without rain. I frequently run shirtless in the rain and take advantage of the cooler weather to do higher intensity work.”

Change of temperature is not an immediate cause of making a person sick

He also stressed that going straight into a cold environment, such as an air-conditioned bus after a run, is not an immediate cause of making a runner get sick. Said Dr Li, “Sudden temperature changes, particularly going from a warm environment to a cold one, can weaken the body’s immune system and make one more susceptible to pick up viruses from other people. But it is not possible to get sick, for example, from walking into a freezer when there is no one else around to infect you.”

Added the doctor, “In the same vein, sudden temperature changes can worsen an existing cold because the body’s immune system is already weakened. The human immune system works best in the context of a fever; it is why we evolved to have a fever in the first place. Cooling the core body temperature abruptly prevents our immune system from working optimally and that is how an existing illness can get worse.”

web counter