How sick is too sick to exercise?

'Tis the season of the sniffles, as well as a host of other nasties. Flu-like symptoms can derail even the most devoted gym goers, though there are those who refuse to let a runny nose wreak havoc on their fitness routine.

But can pushing yourself while under the weather impede your recovery? At what point should people raise the white (snotty) tissue and opt for a comfy couch over a treadmill?

Medical Director at the Australian Medical Association (AMA) Dr Robyn Napier spoke with ninemsn COACH about setting yourself back while you're sick.

"Yes, it's always good to solider on, but you've got to take the bigger picture into account," Napier told ninemsn COACH.

"You've also got to consider how contagious your sickness is."

We asked Napier to shed some light on when you should throw in the gym towel.

She says it's important to trust your instincts and to consider others when contemplating whether or not to power through a cold or flu in the workplace or the gym.

"They're both viruses, so you need rest, fluids, and temperature control," Napier says.

"If you have a fever, that means… [you] might be contagious.

"If you have that profusely running nose, sore throat and cough, that is the time to consider yourself and work colleagues and seek medical advice."

If your cold is compounded with another ongoing illness or serious condition, then it should also be factored into the debate, Napier advises.

"If [you have] an underlying illness, such as asthma or diabetes, your condition may be more complicated and it's worth seeing your GP."