New mothers who are breastfeeding should take regular exercise to prevent a loss of bone density, according to recent research.

Lactating women lose a lot of calcium to their babies, who need the mineral to help them grow.

But a calcium deficiency can lead to a loss of bone density and an increase in the risk of osteoporosis.

Now nutritionists at the University of Carolina have discovered that weight-bearing or aerobic fitness training can help stimulate bone growth and keep the skeleton healthy post-pregnancy.

The researchers measured the bone density of 20 women between one and five months after they had given birth and found that those who did no exercise lost about seven per cent of the bone density in their lower spine.

However, women who did strengthening exercises such as pilates and workouts such as walking or jogging three times a week had stronger bones.

They also regained their figures faster, the study found, even if they paid no special attention to their diet.

Respected personal trainer Jim Stubbs also recommends exercise as one of the best ways of maintaining emotional stability during winter.