Structured Exercise Programs May Improve Artery Health In Older Men

Exercise training programs, rather than testosterone therapy, could improve artery health and function in middle-aged and older men with low-to-normal testosterone levels, according to new research.

As vascular health and testosterone levels decline with age and the risk for cardiovascular disease increases, an exercise program could help men to maintain their heart health, researchers note in the journal Hypertension.

"Earlier studies showed that men who had higher testosterone levels, and who were more physically active, had better health outcomes," said author Dr. Bu Beng Yeap of the University of Western Australia in Perth.

Prescriptions for testosterone have increased exponentially due to the idea that it can preserve heart health, though clinical studies haven't conclusively determined whether testosterone supplementation helps with cardiovascular disease risk, Dr. Yeap said.

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"We expected that the combination of testosterone treatment and exercise training would result in the largest improvement in artery health," he told Reuters Health by email. "What we found was that exercise training did improve artery health, but testosterone treatment did not."

Dr. Yeap and colleagues conducted a clinical trial to study the effects of an exercise program versus testosterone treatment over a 12-week period. They recruited 80 men between ages 50-70 in Perth who had a waist circumference above 37 inches and low-to-normal testosterone levels.

Participants were randomized to either a testosterone or placebo group, and within those, further randomized to either exercise training or no additional exercise. The group that received testosterone treatment applied 2 mL of 5% testosterone cream daily, which is the standard dose used to treat male hypogonadism.

The exercise program, which took place at the Fiona Stanley Hospital gym in Perth, included a circuit with eight machine-based resistance exercises that alternated with eight aerobic stations. Loads were progressively increased every two to three weeks, and participants were required to attend a minimum of two and a maximum of three sessions each week.

During the trial, researchers assessed several indicators of vascular health, including brachial artery diameter and flow-mediated dilation. The vascular endothelium, which is integral to vascular health, can decline with age and lower testosterone levels. Endothelial dysfunction is also an early pathway for atherosclerosis, the authors note.

Overall, 62% of participants who used the testosterone cream saw their testosterone levels rise to at least 14 nmol/L versus 29% in the placebo groups, a significant difference. Neither testosterone nor exercise affected BMI, body mass, waist circumference, glucose or high-density lipoprotein.

Total cholesterol decreased in the testosterone-plus-exercise group, and resting heart rate decreased in both exercise groups.

In terms of vascular health, exercise increased the brachial artery diameter and flow-mediated dilation. Testosterone plus exercise didn't mark a larger increase in vascular measures, and testosterone alone didn't affect the measures either.

"We were surprised by the findings," Dr. Yeap said. "Testosterone treatment did not enhance the effect of exercise training on the health of arteries."

Future studies should test different factors related to testosterone levels, exercise, age and vascular function, the authors write. For instance, researchers might compare the effects of testosterone treatment with or without exercise in men in their 50s separately from men in their 70s. Transdermal testosterone could also differ from intramuscular infections.

"Sex hormones are vital to physiologic function, and it may be that they play an important role in 'transducing' the cell signaling with exercise and are necessary to reap the full exercise training benefits," said Dr. Kerrie Moreau of the University of Colorado Anchutz Medical Campus in Aurora. Dr. Moreau, who wasn't involved in this study, has studied exercise and estrogen treatment in postmenopausal women.

Postmenopausal women who receive estrogen and then exercise, for instance, see benefits, she said. However, men don't experience a uniform decline in testosterone levels as they age, and levels fluctuate on a daily basis.

"Over a decade ago there was increased marketing of testosterone to older men to help boost energy and vitality, and perhaps a lot of these men really didn't need it because they had normal testosterone levels," she told Reuters Health by email. "Overall, exercise is beneficial for vascular health in men, but the role of testosterone in exercise training benefits is complex and warrants further research."

—Carolyn Crist

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