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Just two weeks of reduced activity increases body fat and decreases muscle strength, particularly among seniors

New research highlights the importance of getting out and staying active during the winter months.

New UK research has shown that although it might be difficult to get out and about on cold, dark winter days, it's important we all try to keep moving to preserve muscle mass and avoid weight gain, particularly for seniors.

Carried out by researchers at the University of Liverpool, the new study looked at 47 participants who were all walking over 10,000 steps per day, but did not do any vigorous exercise.

The participants were split into two groups depending on their age, with 26 subjects in their 20s and 30s placed in the younger group, and 21 subjects in their 50s and 60s places in the older group. 

At the start of the study, the researchers carried out tests to assess various physiological measures such as participants' lean mass, bone mineral density (BMD), muscle function and strength.

The participants were then asked to reduce their physical activity to just 1,500 steps a day for a period of 14 days, before going back to their usual 10,000 steps a day for another 14 days.

The findings, presented at The Physiological Society's conference Future Physiology 2019, showed that after just two weeks of reduced physical activity, muscle size, muscle strength and bone mass was equally reduced in both the younger and older groups. The two groups also gained a similar amount of fat around their waist and in their muscle tissue, which reduces its quality, leading to significant reductions in muscle strength.

However, as the older adults had less muscle and more fat to begin with, these changes are likely to have a bigger negative effect on this population, compared with younger adults.

Moreover, the researchers found that there were two physiological measures that decreased substantially in the older group but not among the younger participants -- cardiorespiratory fitness (CRF) and mitochondrial function. CRF is how efficiently oxygen is supplied to muscles during sustained physical activity, with low CRF usually found in those with poor physical health and linked with developing diseases at a younger age, while mitochondrial function, which is the energy production of our cells, is important for muscle and metabolic health. The declines in both CRF and mitochondrial function may also be linked to the loss of muscle mass and strength and the gains in muscle and body fat during the period of physical inactivity.

Researchers Juliette Norman commented on the findings saying, "The severe impact of short-term inactivity on our health is hugely important to communicate to people. If the gym is hard to get to, people should be encouraged to just meet 10,000 steps as even this can guard against reductions in muscle and bone health, as well as maintaining healthy levels of body fat."