My training partner has accused me of being addicted to exercise. How do I know if he's right?

Exercise addiction is an increasingly common disorder, predominantly in women. However, it can be positive or negative. Those with a positive addiction schedule exercise sessions around other aspects of their life (social, relationships and career) so it's not detrimental to wellbeing. Negative addiction is a compulsive desire to exercise that overrides such considerations.

Characteristics of negative addiction include: a desire to exercise at ever increasing intensities, anxiety or fatigue when unable to exercise, an inability to reduce the amount of exercise you do, excessive time dedicated to it and continuing to exercise despite recurring physical problems caused by it. If you display three or more of these characteristics, you fulfil the criteria for diagnosis as an addict.

Over-training with inadequate rest is a major physical problem. Symptoms include suppressed immune system, higher resting heart rate (check on waking for five consecutive days), loss of appetite, decreases in testosterone and overall performance. If that rings bells with you, apply some self-help strategies and/or seek professional help. Cross training can avoid overuse injuries, while aerobic, strength and flexibility work creates a balanced programme. Schedule in rest after two consecutive sessions, and one day a week of complete rest. Also, try stress management techniques such as yoga, t'ai chi or meditation.

· Joanna Hall is a fitness expert (joannahall.com). Send your exercise questions to Weekend, 119 Farringdon Road, London EC1R 3ER (weekend@theguardian.com).