Q I’ve recently taken up running, after losing 115lbs in 18 months and giving up smoking after 25 years. I’ve been running for about 20 minutes every morning for four months, but my goals are to build this up to 45 minutes, five times per week and to lose three and a half stone more. At the moment I always seem to be out of breath – will it ever get any easier?

A I’m delighted to hear that you’ve quit smoking and lost so much weight; in terms of your long-term health, this will prove to be the best decision you ever make.

I would advise you, though, not to rely exclusively on a high-impact activity like running for your aerobic exercise; try some low-impact alternatives, such as cycling or rowing, as well.

Another low-impact alternative to running that you could try is brisk walking up a hill. Hills provide a very good environment for high-intensity interval training, which involves short bursts of intense activity interspersed with recovery periods. High intensity exercise burns lots of calories, so it’s ideal for you.

Find a hill long enough and steep enough to take you about two minutes to get to the top while walking as fast as you can. If you can’t find a hill, a long flight of stairs will do. Complete six repetitions, with a slow walk back to the foot of the hill as your recovery. That’s only 12 minutes of hard exercise, but the number of calories burned will be about one and a half times that burned during a 20-minute jog. As you get fitter, you can increase the training load by doing more repetitions (up to about eight) and increasing your pace – or find a steeper hill!

Setting goals is also a good idea, but you need to be clear about your reasons for setting your goal of running for 45 minutes. If it’s because you want to be able to run a 10K, then it’s a reasonable target. But if it’s simply because you want to be able to exercise for longer, so that you can use more calories to help with your weight loss, there are better ways of doing so. In this latter case, my advice would be to increase the pace of your 20-minute run so that you run harder, and then increase the duration to about 30 minutes. This will make optimal use of your training time, and reduce the risk of overuse injury.

As for whether running gets any easier, the answer is a resounding ‘yes’. You haven’t said what you currently weigh, but if we assume that you are still three and a half stones overweight, you’re still carrying a lot of extra mass. It’s as if a lighter runner was out for a run carrying a rucksack containing 20 bags of sugar – they’d find that hard work. And not only do you have to work to carry the extra weight, it also interferes with your breathing – as you have discovered. Breathlessness during activity is a common problem for people who are overweight. As the pounds peel away, you will find your breathing becoming easier and the pace of your running increasing. Keep up the good work, and stay off the cigarettes!

—Alison McConnell, exercise scientist and respiratory physiologist