Overweight, diabetes and cardiovascular disease are all linked. Put simply: if you have too much fat tissue your insulin sensitivity decreases, and the amount of glucose in your blood increases. Your liver absorbs some of the glucose and uses this to make ‘bad’ cholesterol. This bad cholesterol damages blood vessels and as a result your chance of having a heart attack or stroke increases.
In 2011 American sports scientists published the results of a study, in which they examined whether strength training could alter the interplay between overweight, diabetes and cardiovascular disease in overweight people, in the International Journal of Sports Medicine. The researchers got 9 post-menopausal women, all aged between 60 and 70 and with an average BMI of 32, to do weight training for 12 weeks.
If overweight women take up weight training their cholesterol levels improve. The effect isn’t overwhelming, but it’s big enough to reduce their chance of having a heart attack.
The women trained three times a week and each session consisted of a full-body workout. The women did chest press, lat-pulldown, shoulder-press, seated-rows, leg-abductions, leg-adductions, chest-flies, de leg-press, leg-curls and leg-extensions. The women did 3 sets of 8 reps for each exercise; the last set each time was at failure.
A control group of twelve women didn’t train.
A single training session had no effect on the triglyceride or cholesterol concentration in the blood, but after 12 weeks the LDL cholesterol concentration (LDL = bad), the triglyceride concentration (triglycerides = even worse) and the non-HDL cholesterol (non-HDL cholesterol = all bad things together) concentration had decreased by 23, 16 and 20 percent respectively.
According to cardiologists, the chance of a heart attack or other “nonfatal coronary heart event” decreases by 4.4 percent for every mmol per litre decrease in the LDL cholesterol concentration.
“In this study, 12 weeks of resistance exercise training reduced LDL-cholesterol by 0.77 mmol per liter, which may translate to a 3.4 percent reduction in risk of a nonfatal coronary heart event in this group of women”, the researchers write.
In comparison, sponsored studies show that statins can reduce the LDL cholesterol level so much that the chance of a nonfatal coronary heart event decreases by thirty percent.
But still, a decrease of 3.4 percent through strength training is of course better than none at all. In addition, the researchers hope that the positive cardiovascular effects of strength training may increase in the longer term.
The women in the group that trained gained strength, but changes in body composition were not statistically significant.
“Interestingly, in this study the effect of resistance training on lipid and lipoprotein-cholesterol concentrations was independent of changes in BMI and body composition”, the researchers write. “Furthermore, these results provide support for the use of whole body resistance training in obese, postmenopausal women as a non-pharmacological approach for the reduction of lipid and lipoprotein-cholesterol concentrations.”
Resistance exercise and lipoproteins in postmenopausal women.
The specific aims of this study were to quantify the effects of 12 weeks of resistance training, as well as a single session of resistance exercise on lipids and lipoproteins in obese, postmenopausal women. 21 obese, postmenopausal women, not on hormone replacement therapy (age=65.9 ± 0.5 yr; BMI=32.7 ± 0.8 kg/m(2)), were randomly assigned to control (n=12) and exercise (n=9) groups matched for age and BMI. For 12 weeks, 3 days/week, the exercise group performed 10 whole body resistance exercises (3 sets at 8-RM). Fasting (10 h) blood samples were collected immediately prior to and 24 h after the first and last exercise and control session. Serum was assayed for concentrations of total cholesterol, triglycerides, LDL-C, HDL-C, HDL 2-C, HDL 3-C, non-HDL-C and TC:HDL and LDL:HDL ratios. The exercise group exhibited a significant (P<0.01) improvement in muscular strength, but no change in BMI, body mass or body composition post-training. Total cholesterol, LDL-C and non-HDL-C were significantly (P<0.05) lower in the exercise compared to the control group following the 12 weeks of resistance training. Whole body resistance training provides obese, postmenopausal women a non-pharmacological approach for the reduction of lipid and lipoprotein-cholesterol concentrations.
© Georg Thieme Verlag KG Stuttgart · New York.
PMID: 21086242 [PubMed – indexed for MEDLINE] PMCID: PMC3354704