SUMMER holidays might be on the horizon but there are exams to get through first - meaning endless hours of revision for students of all ages. Faced with reams of paper to shuffle and complex terms to memorise, it's all too easy to stay up late, fuelled by coffee and chocolate - or escape and hide in front of the TV, mindlessly gobbling junk food.

As revision time gets underway, students need to make sure they bone up on the health basics so they can sail through studying and ensure peak performance in the exam room.

Tracey Williams, parenting expert for lifestyle website iVillage.co.uk, says increased competition for university places means students face more pressure than ever. And while it's natural to feel a little nervous, Williams says some students may become anxious or depressed, and feel unable to cope.

She says signs to watch out for include irrational panic attacks, being uninterested in others' company, loss of appetite, complaining about sleepless nights or being unable to get up in the morning, and taking no pleasure in life outside revision.

GP Rosemary Leonard knows all too well what coping with studying teenagers is like - her son is preparing for GCSEs and a niece is swotting up for her International Baccalaureate.

''My big challenge at the moment is stopping my son from snacking on chocolate all the time,'' she sighs. ''But I was with my niece last weekend - and to say she was moody would be an understatement.''

Leonard says keeping cool during exam time is a question of balance.

''You want a balance between relaxation, sleep, studying and exercise,'' she says.

Both experts emphasise the importance of a healthy diet, particularly during revision time. ''You should be cutting out junk food, eating lots of fresh fruit and vegetables and drinking lots of water,'' says Williams.

Leonard points out that food is a popular form of procrastination for teenagers studying at home - when faced with piles of textbooks it's all too tempting to get up and graze from the fridge or larder.

''Healthy meals are really important,'' she stresses. ''Try not to let them snack between meals because it's just another distraction. Caffeine can help concentration, but if you overdo it you'll become jittery and unable to sleep or rest. There is also some evidence that Omega 3 fish oils may help nerve function, but I'm not sure whether it really makes a difference if you are eating a healthy, balanced diet.''

Either way, Leonard suggests eating oily fish twice a week and getting a good night's sleep. ''Everyone has their own pattern when they work best, but getting eight hours of sleep is very important,'' she says. ''There's no point in working through the night, quality revision is best.''

All work and no play is not the way to exam success, and Leonard says taking time out will help your teenager cope with the pressure. ''Getting out and doing something really physical is very important, whether it's playing tennis, kicking a football around or having a game of rugby. It's good to get out there and have a run around - or join an exercise or yoga class.''

Studying teens should get involved in some form of exercise every day if possible, or at least every other day. Leonard has good news for those who like relaxing in front of the TV, too. ''There's a lot to be said for just sitting down and watching your favourite TV show - as long as you're not watching for hours.''

If they're beginning to feel the heat, Leonard recommends a few ground rules to stop the exam period turning into a testing time for the whole family. ''Keep their behaviour within reason,'' she says. ''It's OK to cut them some slack, but if they are becoming anti-social, they need to be told.''

If girls are due to get their period at exam time and they suffer from bad period pains, Leonard suggests they see their GP and discuss ways to delay their period.

For some students, the end of exams can be almost as stressful as revising, as they panic about not having worked hard enough. Leonard says it's essential to keep positive and not worry. ''Don't beat yourself up if you think you've done something wrong, move on to the next one. Once they're over, put them behind you and don't get stuck mulling over them,'' she says.

While finishing their exams may be enough of a reward for some students, she suggests that others might benefit from planning a treat to look forward to when the swotting is done.