Exercise for Everyone

Exercise
The following article was written after I was asked to give a presentation on the older female athlete at the South African Menopause Society Symposium in Feb 2010.

It became clear immediately that very little research had been done on the older athlete. However there was a large body of research that had been done on the benefits of exercise. This research, done on large groups of people showed that not only did exercise prevent heart attacks, it reduced the incidence of cancer, strokes, Alzheimers and depression. We are not talking about running marathons. These were people who exercised moderately i.e. walking for 30 minutes four times a week. We all want to be healthy until we die and the best way of ensuring this is to exercise. It has to be part of your routine. Often exercise is delayed because something seemingly more has come up. You owe it to yourself to make it a priority. Join a walking group in your area today!

THE FEMALE ATHLETE AFTER 45

The female athlete after 45 has been for the most part neglected by researchers. Older athletes can still be competitive. They have a right to know what to expect as they age and whether it is possible to delay the inevitable effects of ageing on performance.

Sporting performance will first be affected by changes in skeletal muscle. In men, skeletal muscle and muscle strength are directly related to testosterone. Testosterone levels peak in early adulthood and decline gradually from the age of 30. Muscle strength declines by about 2% a year so that a 70 year old man will be 40% weaker than his 30 year old counterpart. Skeletal muscle has a high metabolic rate. It is likely to be replaced by fat with a much lower metabolic rate.

Later cardiovascular and respiratory systems will be affected. The heart will be less effective as a pump and the lung capacity will decrease. As we age we compromise our activities. It becomes difficult to walk or climb stairs or lift objects so we avoid doing these things. This inactivity leads to further weakness. Quality of life is compromised. Weakness will lead to falls further increasing morbidity and mortality. Regular exercise has been shown to postpone these changes.

If we look at men’s world record marathon times according to age we see that times are good until the seventh decade when there is a rapid deterioration. Haile Gebreselassie has the world record time of 2:03:59 at the age of 34. A Japanese man has run a 2:36 marathon at the age of 60 and a Canadian has run a 2:59 marathon at the age of 72.

Women’s world record marathon times according to age show that the decrease in performance occurs earlier. Paula Radcliffe has the world record time of 2:15. The record at 55 years is 2:52 at 60 3:02 and at 70 3:44. From the graph it is obvious that the decline in performance occurs earlier in women and occurs at about the time of the menopause. (Graph 1) Female weight lifters are totally dependent on muscle strength. The ability to lift weights declines from the mid forties.

If muscle strength is related to testosterone in men it seems logical to propose that the decrease in performance in women in the midlife should also be hormonally related.

Skeletal muscle has estrogen receptors(ER) on the cell membrane, the nuclear membrane and in the cytoplasm. The ERs are mainly found on Type 2 or fast twitch muscle fibres and these are the ones that atrophy with age. Type 1 or slow twitch fibres are largely unaffected by age. Estrogen enables the muscle to use fat a as well as glycogen as an energy source. This explains why women are better endurance runners than men. Estrogen also protects the cell membrane against injury. Older female runners maybe more prone to injury.

Several studies have tried to ascertain whether the menopause is associated with a loss of muscle strength in the general population. A recent study from Taiwan looked at 979 women aged 43 to 57. They classified them into premenopausal, peri menopausal and postmenopausal according to menstrual history. They looked at flexibility, grip strength and balance. Flexibility and balance with eyes closed were unrelated to menopausal status. Grip strength which is directly related to muscle strength was significantly related to menopausal status. Peri menopausal women had 9.4% weaker grip strength than premenopausal women and postmenopausal women were 15.2% weaker. Balancing with eyes open was also affected - 5.5% and 16.5% shorter times respectively. Surprisingly self reported exercise and hormone use did not influence results.

A small randomised control trial study from Finland looked at women between 50 -55 who were menopausal from 6 months to 5 years and who had never taken HT. They divided them into 4 groups 1. Exercise 2.Hormone therapy and Exercise and 3.Hormone therapy only and 4.No intervention. Kliogest was used as hormone therapy. Both exercise and hormone therapy increased muscle strength and the combination was synergistic. Only the combination of exercise and hormones compared to no intervention reached clinical significance.

A study of monozygotic twins showed that estrogen use improved exercise performance. Fifteen twin pairs aged 54 – 62 discordant for hormone therapy with a mean use of 6.9 years were studied. Hormone therapy was associated with greater muscle power and decreased muscle fat content. Tibolone was used by four of the women and they had an increased muscle cross sectional area compared to their non using twin.

Rats run approximately 6 kilometres a day on a wheel. After oophorectomy rats stopped running. When oestrogen was given running activity returned almost to the previous level. The effect was immediate and could not be related to a skeletal muscle effect. It seemed likely that the lack of oestrogen made the rats too tired to run.

It seems that muscle strength does decrease at the time of the menopause but whether estrogen treatment can alleviate this loss seems unclear. A meta-analysis looking at 24 studies concluded that estrogen therapy in the menopause can increase muscle strength by 5%. This is modest when resistance training alone has been shown to increase muscle strength by 8-14%. It seems likely that other factors are contributing to the decrease in performance. The role of testosterone has not been examined in women. Testosterone levels decrease in the peri menopausal period and then remain stable. Bilateral oophorectomy causes a sudden 50% decrease in testosterone levels. In athletes this could be extremely detrimental.

There are actually very few studies of older female athletes. There is a group in Sweden who has studied a group of 20 previously elite athletes mean age 56. Seventeen were runners, 2 were skiers and 1 was a swimmer. All but one continues to participate in their sport on a recreational level. They were compared to a group of healthy sedentary controls. The athletes as expected had a greater exercise capacity. Three of the 20 (15%) compared to 9 of the 19 controls (47%) had nonpathologic ST depression on exercise ECG. The significance of ST depression in healthy asymptomatic women is uncertain but may indicate a risk for later cardiac events.

Endothelial function was studied in this same group of women. A non-invasive ultrasound technique, flow mediated vasodilatation (FMV) has been shown to correlate with a risk of atherosclerosis and is an early marker for cardiovascular disease. Estrogens promote rapid vasodilatation by directly activating the production of nitrous oxide in endothelial cells. Estrogens also favourably alter lipid profile. Athletes not using HRT had the highest mean FMV value. It was significantly higher than sedentary controls not using HRT. It was higher than athletes and controls using HRT but this did not reach significance. It seems that exercise induces maximal vascular reactivity and that further improvement with HT cannot be attained. In the control group hormone use had a beneficial effect on FMV.

Running is beneficial for bone density. A study of runners participating in the London marathon looked at 217 males and 184 female runners aged 20 to 93 compared to 267 male and 334 female controls aged 20 to 80. The runners had a significantly higher bone density than the nonrunners. There was a decrease with age but this was attenuated in the runners.

There is a group of runners with the female triad of nutritional disorders, menstrual irregularities and osteoporosis. This, like any eating disorder is confined mainly to young females. In this situation a team approach using a psychologist, a dietician and a gynaecologist will be necessary. It is possible that osteoporosis will continue to be a problem as they age. These runners will benefit by being given hormonal therapy.

There is a common perception that running is bad for you. Occasionally a runner dies in a marathon event. It is widely believed that running is bad for joints especially the knees. A cohort study done in the USA looked at runners belonging to a nationwide running group. They had to be older than 50 in 1984. 538 runners were compared to 423 healthy university colleagues and have been followed up for 21 years. Self reported functional ability in 8 areas; rising, dressing, grooming, hygiene, eating, walking, reach, grip and routine physical activities as well as mortality were examined. The runners at baseline were thinner and less likely to smoke. Throughout the study they continued to exercise more. The runners had much lower disability scores. The disability differences for women were the most striking. Fifteen percent of runners vs. 34% of controls died. This reached significance even when controlled for smoking and obesity. Not only was there a reduction in cardiovascular deaths but also cancers and neurologic disorders.

It is clear that lifelong exercise improves quality of life and prevents disease. Is middle age too late to start? Another large cohort study from Sweden followed up 2205 men aged 50 in 1970-1973 and re-examined them at 60, 70, 77 and 82 years. The absolute mortality rate was 27.1, 23.6 and 18.4 in the low, medium and high physical activity groups. Men aged between 50 and 60 who increased their physical activity rate from low and medium to high continued to have a higher mortality rate for the first 5 years but after 10 years it was as low as the high activity group. This was independent of smoking status.

The Nurses Health Study and WHI observational study have showed that exercise is inversely correlated with mortality in women as well. NHS women who exercised less than 1 hour per week had a 58% increased risk of coronary heart disease as compared to women exercising 3.5 hours per week. This remained significant after adjusting for BMI, smoking and lipids. There was also a decrease in cancer deaths and dementia in the exercising women.

Exercise has been shown to be beneficial for depression, for delaying onset of Alzheimer’s, for cancer survivors. No drug has been shown to delay the onset of Alzheimer’s but it seems that exercise can.

The female athlete will be the least worrisome of your patients. She will be at lower risk for cardiovascular disease, osteoporosis, cancer and Alzheimer’s. Hormonal therapy (HT) can be prescribed on conventional lines. Estrogen use maybe helpful in maintaining muscle strength. HT in athletes probably does not have any additional cardio protective benefit as exercise alone is sufficient. Convincing your postmenopausal patient to exercise may be the most important thing that you can do to improve the quality of the rest of her life.

CONCLUSIONS:

Muscle strength decreases at the time of the menopause.

This is only partly estrogen related.

Exercise into old age decreases morbidity and mortality.

It is never too late to start exercising.

Contact Details

Dr. Alice Shaw
Pr No.:1606263


dralice@aliceshaw.co.za
Tel: 044 384 0926
Fax: 044 384 0970