at our heart-rate monitor or stopwatch," says Bill Black, who coached the GB Men's Triathlon Team at the Sydney Olympics. "But if we train at a certain pace in the pool we can keep cross-checking with the clock - plus every length is usually 25 metres

.”He started by devising a simple experiment with a small group of subjects who ran or bicycled for 40 minutes at 76 per cent of their maximum heart rate, and then had blood samples drawn immediately after exercising. Next the blood samples were flown to a

boys' lungs are developed by the age of 16. Maximum heart rates in children may reach 220 or even 225 before puberty, but tend to fall to around 200 in the late teens." The main thing to concentrate on at an early age is skills," says Denmark. "You have

of anyone’s diet.Over the past decade, researchers have discovered that people who eat fish and other seafood a few times per week have a lower risk of sudden heart attack, vascular disease and stroke. Fish intake has also been linked to lower rates

, an indication that a significant contribution is being made from the anaerobic energy system. Training intensity therefore needs to be low - around 55-70 per cent of maximum heart rate, or conversational effort (if you can't easily carry on a conversation

) will also help you get faster.The question of how fast you should go during these bursts of speed depends on the individual. Nevertheless, the best training effect is gained when your pulse rate is somewhere between 70 and 85 per cent of maximum. This should

too could hold back the years. 20s Your running may still be improving, but your heart is already slowing down – by around one beat per year. Your maximum heart rate controls the oxygen pumping round your body, as you age less oxygen is available

run be compared with marathon pace? At the moment there seems to be about a 2:00 min/mile difference between my fastest and slowest runs. Should I be aiming for steady pace or go by perceived effort or heart rate? SusiebuzzA. Pacing is essential

with 10 minutes of very easy running and walking. Stretch gently for a few minutes and mix in four or five 100m strides (at 90 per cent of maximum speed) to get you ready for the upcoming effort. To keep your heart rate up, move around or jog on the spot

it there.Rudd has been competing in triathlons since 1994 and has firm ideas about the swim. "It's about thinking and training smart," he says. "If you only have a few hours in the water each week, you need to use every single minute to its maximum."If your