Those who are embarking on a course of exercise for the first time in a long while should consult a doctor, especially if they have chronic problems.

People with high blood pressure, for instance, should be careful when doing weight training, said Dr Benedict Tan, who is chairman of Exercise is Medicine Singapore.

"You don't want to do activities that involve a lot of breath-holding or straining as that could precipitate a stroke," he said.

Similarly, someone with osteoporosis - in which the bones become brittle and fragile - should avoid intense contact sports.

Dr Derek Li, a general practitioner at Raffles Medical, suggested that people fill out what is known as a Physical Activity Readiness Questionnaire.

Such questionnaires can be found online, including on the Sport Singapore website.

If people answer yes to any of the questions - such as if they feel chest pains during physical activity - they should check with their doctor before becoming more physically active.

This is especially the case for people past their physical prime who tend to overstretch themselves when they pick up exercise after a long hiatus.

Dr Li said: "You remember the kind of energy levels you had when you were younger, but you don't realise that your body cannot handle that intensity anymore."

Dr Tan Chyn Hong, an orthopaedic surgeon at Mount Elizabeth Novena Hospital, said that it is important to continue doing different types of exercises as people become middle-aged.

"You can't just keep doing cardio exercises without doing strength exercises," he said. "What will happen is that you will become so lean, you will lose all your strength."

Meanwhile, those who are obese and trying to lose weight should not start out with exercises that put too much strain on their joints, such as running.

"Start with static exercises such as light squats or spinning in the gym," suggested Dr Li.

"Otherwise, if you are overweight, your body may not be able to take it."

Linette Lai