Matt Seaton, 39, Guardian journalist and amateur racing cyclist

In the summer I race once or twice a week. I also get up early on Sunday and do a three-hour, 50-mile ride. In addition, I will have done one early-morning session on an indoor trainer (or "turbo" trainer, which is similar to an exercise bike).

The secret is to use a heart-rate monitor, know your zones (based on percentages of your maximum heart rate), and train using "intervals" - short, intense efforts interspersed with periods of recovery. You have to be motivated because it hurts. It's also very boring, but the pay-off is that it is very effective.

I probably train five to eight hours a week, including racing. A lot of the people I compete with probably do double that. Arguably, bike racers are treading a line where they have to be fitter than is strictly good for them. For "normal" people, I'd think a compromise of longer sessions at moderate intensity is more beneficial than the two-minute max-out.

Sam Murphy, 36, fitness writer and marathon runner

My normal regime is to go for four runs a week. I go for one long run of 60-90 minutes. I also have a short "threshold" session where I'll run intensively for 20 minutes on a treadmill, so I can control my environment. I'll also do a steady 40-50 minute run, when I'll take the dog and look at the scenery. There will be one further session that will be dictated by my club - it may be an interval session, perhaps with repeats up a hill and recovery periods in between. On top of all that, I'll do two gym sessions a week.

The new report is interesting; it backs up other recent findings - the general consensus on cardiovascular exercise seems to be that intensity and quality are more important than quantity. The key point is you have to have a good level of fitness before you could tackle such high-intensity exercise.

You can only work at such a high level for a short time. It is debatable that anyone who cites "lack of time" as a reason they aren't able to get fit would be able to work at the 95-100% intensity level that would be necessary for this type of training.