I had to stop going to the gym because I felt flu symptoms - weak, shivery and tired - the following day. I put it down to the air conditioning in the gym and gave up my membership. My friend has taken up outdoor tennis and is experiencing the same symptoms. What could be causing this and how can it be avoided?

There is nothing mysterious going on here. It seems you and your friend are suffering from post-exercise exertion. Muscle tiredness and weakness are quite normal the day after a heavy exercise session. Also, muscles might twitch and feel shivery. Remember, extreme physical exertion can even cause nausea and vomiting, as sometimes seen in long-distance runners, for instance. Next time, just take it easier and drink plenty of fluid. And exercise away from air conditioning machines. A wrong conclusion would be to stop exercising altogether.

I've had two bouts of tonsillitis since December last year and have had a sore throat since, although the tonsillitis was treated with antibiotics. I have a stinging, hot sensation at the back of my throat and my voice cracks if I try to talk for more than an hour. I visited an ear, nose and throat (ENT) consultant who was not particularly helpful and advised I take antacids. I am avoiding cold foods/drinks, smoky places and raising my voice, and I drink 2-3 litres of water a day. None of this seems to be helping. I have to begin teacher training in September and am anxious about not being able to use my voice properly.

This seems to be a problem that should be followed up by an ENT specialist. You should persist and obtain another appointment, possibly with a different ENT doctor. This is particularly important with regards to your job.

Four months after having my baby my hair started to fall out. It is now very thin. I take spirulina and also saw a homeopath. Are there any supplements you could suggest?

The hair loss you are suffering could be an adverse event to the supplements you are taking. Consider stopping them for a time and see whether this affects the hair loss. There is no convincing evidence that spirulina or homeopathic remedies are helpful for hair loss.

· Max H Pittler is deputy director of complementary medicine, Peninsula Medical School, Universities of Exeter and Plymouth. Before following Max's recommendations, you should consult your GP about any medical problems or special health conditions. Send your questions to Wellbeing, Guardian Weekend, 119 Farringdon Road, London EC1R 3ER. Email: ask.max@theguardian.com.