The small blood vessels in muscles of women after menopause are less able to grow compared to those of young women, according to new research published in The Journal of Physiology.
This means exercising before menopause is all the more important for women to develop blood vessels in muscles, and thus the ability to develop muscle strength.
Recent studies have shown that there are substantial differences between women and men in the way ageing affects blood vessels, which influences susceptibility to conditions like heart disease and stroke. These differences are largely related to the female oestrogen.
Oestrogenis protects the heart and blood vessels in women for about half of their lives, but at menopause there is an abrupt permanent loss of oestrogen, leading to a decline in the health of our blood vessels.
In this study, the researchers at the University of Copenhagen examined the smallest of blood vessels in muscle, called capillaries.
The number of capillaries in skeletal muscle can change a lot and is mainly affected by how much the muscle is used, such as during exercise.
This is the first study to isolate and examine cells from skeletal muscle samples of young and old women.
Capillaries in skeletal muscle (as opposed to heart muscle) are very important for skeletal muscle function, physical capacity and health as it is here that oxygen and nutrients, such as sugar and fats, are taken up into muscle when needed.
It is known that loss of capillaries in muscle can affect insulin sensitivity and thereby the development of Type II diabetes.
The study also found that when the aged women completed a period of aerobic exercise training by cycling, they did not achieve an increase in the number of capillaries in muscle, in contrast to what has been repeatedly shown in young and older men.
Ageing is known to lead to a loss of capillaries in the muscle, an effect which, in men, has been shown to be counteracted by a physically active lifestyle.
This new study suggests that women do not attain capillary growth as readily and that an underlying cause may be a flaw in the cells that make up capillaries.
Both men and women enjoy a vast benefit from being physically active throughout life, regardless of age, but the current study supports the idea that women may benefit from being physically active before menopause, while they still have oestrogen, so that they have a good physical starting point as they get older.
The researchers studied older women (over 60) and young (around 25) ones.
The women underwent a series of physical tests and the researchers obtained small samples from their thigh muscles.
The muscle biopsies were used to isolate blood vessel cells and muscle cells for further study in the lab.
The older women then also did 8 weeks of cycling training, where they trained three times per week at moderate to high intensity.
The women were tested for fitness and several other parameters before and after the training.
After the training period samples were again obtained from the thigh muscle and used for analysis of capillary number and specific proteins.