Information from the recent World Congress on Insulin Resistance, Diabetes and Cardiovascular Disease
Exercise provides important and varied benefits for individuals with cardiometabolic disorders regardless of experience level, and certain exercise types may yield better outcomes for those with certain conditions, according to a speaker at the World Congress on Insulin Resistance, Diabetes and Cardiovascular Disease.
“It’s never too late to start exercising to have a significant profit from it,” Nikolaos Perakakis, MD, PhD, instructor in medicine in the endocrine division at Beth Israel Deaconess Medical Center and Harvard Medical School, said during a presentation.
Myriad benefits of exercise
Previous research has demonstrated that risk for all-cause mortality, cancer mortality and CV mortality can be cut by 40% to 60% by incorporating a daily routine of 30 minutes of physical activity, he said.
With metabolic syndrome, regular exercise has been shown to reduce individual components, including waist circumference, triglycerides, blood pressure and fasting glucose. In a recent systematic review and meta-analysis published in Metabolism, van Namen and colleagues reported that a supervised lifestyle intervention incorporating regular exercise and diet change reduced the prevalence of metabolic syndrome by 39%. Perakakis said aerobic exercise alone appears to yield the most benefit for patients with metabolic syndrome.
“Aerobic exercise actually [is] as effective or even more effective than combined aerobic and resistance exercise in patients with metabolic syndrome,” Perakakis said.
For patients with type 1 and type 2 diabetes, benefits such as improved glycemic control and less insulin resistance are attainable via increased physical activity, particularly aerobic exercise.
Type of exercise also plays a role for patients with nonalcoholic fatty liver disease, Perakakis said.
“In contrast to what we see in type 2 diabetes, in nonalcoholic fatty liver disease, anaerobic exercise seems to be much more beneficial,” Perakakis said, noting that anaerobic or resistance exercise “shows more robust decrease[s] in intrahepatic lipid percentage compared with aerobic exercise.”
The reasons underlying the differences by type of exercise are unclear, he said.
“We don’t have a clear explanation for this from a pathophysiological point of view. We think, though, that … aerobic exercise is focusing more on lipolysis or is acting more on adipose tissue … whereas resistance exercise is acting more directly on the liver,” Perakakis said.
Perakakis also rejected the notion that exercise is beneficial only if started at a younger age and maintained into later life, or if workouts are particularly grueling.
“It seems that exercise has profound effects on metabolic outcomes, but we often hear the argument that this probably is effective in people [who] are training a lot for many years and they started early,” Perakakis said.
In a study published in BMJ in 2019, participants (mean age, 58 years) who had very little history of physical activity and increased their amount of exercise to an average of 6.4 kJ/kg per day — in line with WHO recommendations — experienced a 24% reduction in all-cause mortality during follow-up (HR = 0.76; 95% CI, 0.65-0.88).
Perakakis also said it is more important to reach the WHO recommendation for physical activity, which calls for 150 minutes across 3 days or more each week, than it is to work out at “high intensity.” Research to date has demonstrated no “profound difference in metabolic benefit” between levels of exercise intensity, he said.
Getting past roadblocks
Despite available evidence showing positive outcomes of regular exercise, many individuals do not or are unable to follow the WHO’s recommendation for exercise, including patients with diabetes.
“There are different reasons for that. …One is that exercise can be boring, especially if we don’t combine it with sports or with friends,” Perakakis said.
Patients with diabetes, for example, may have additional barriers. “For example, [patients with diabetes] may have a low fitness level, they may be overweight or they may have fear for hypoglycemia and cardiovascular events that can be triggered with exercise,” he said.
Perakakis also noted that the presence of concomitant conditions such as nephropathy, neuropathy, retinopathy and diabetic foot disease can make regular exercise even less likely.
“It seems that it would be difficult also for these people to motivate them and make them train,” Perakakis said. “This has pushed science in order to investigate the physiological mechanisms related to the beneficial effects of exercise, and we can actually develop treatments that can mimic the beneficial effects of exercise.”
Among these mechanisms, Perakakis pointed to hormones produced by muscles called myokines that are responsible for benefits for insulin sensitivity and inflammation, among others. Finding other treatment targets at the cellular level will be important going forward.
“The future direction of research is focusing on the identification of genes and molecules that are responsible for these beneficial effects of exercise as well as combination of diets with exercise or coordination of nutritional intake with timing of each exercise,” Perakakis said.
In addition, investigations and treatments must incorporate individual factors.
“A lot of patients are also looking for personalized protocols since we now know that not all people respond the same to exercise,” Perakakis said. “And finally, a big area of research is exercise in childhood, where we know that also the ranges of exercise are variable and we have increased rates of obesity and metabolic syndrome.”
Perakakis N. Exercise, Insulin Resistance, Diabetes and Cardiovascular Disease. Presented at: World Congress on Insulin Resistance, Diabetes and Cardiovascular Disease; Dec. 4-7, 2019; Los Angeles.
Mok A, et al. BMJ. 2019;doi:10.1136/bmj.l2323.
van Namen, et al. Metabolism. 2019;doi:10.1016/j.metabol.2019.153988.