Exercise & Health

A small study involving 30 older adults (60+) with amnestic MCI, has found that those who underwent a year of aerobic exercise training showed a 47% improvement in some memory scores, compared with minimal change in those who participated in a stretching program. Moreover, brain scans showed the exercise group increased blood flow into two critical brain regions: the anterior cingulate cortex and the hippocampus.

https://www.eurekalert.org/pub_releases/2020-05/usmc-eim051820.php

Thomas, Binu P. et al. 2020. Brain Perfusion Change in Patients with Mild Cognitive Impairment After 12 Months of Aerobic Exercise Training. Journal of Alzheimer’s Disease, 1 Jan. 2020: 617–631.

Research using data from 2131 participants in the 2008 U.K. Health Survey suggests that regular exercise can partly counteract the negative health effects of being sedentary. The analysis grouped people into the following categories:

• physically active and low sedentary 'busy bees' (18.6% of the sample)
• physically active and high sedentary 'sedentary exercisers' (36.7%)
• physically inactive and low sedentary 'light movers' (6.8%)
• physically inactive and high sedentary 'couch potatoes' (37.9%).

Overall, physical activity was significantly associated with lower BMI, lower waist circumference, lower HbA1c levels (HbA1c is a modified form of haemoglobin, commonly used to measure glucose concentration; higher levels indicate poorer control of blood glucose levels), and higher HDL-cholesterol (the 'good' cholesterol). Sedentary time was associated with lower HDL-cholesterol levels.

None of that is a surprise, of course. The interesting aspect of this study is its attempt to disentangle physical activity and sedentary time.

In comparison to the couch potatoes, both busy bees and sedentary exercisers had significantly lower BMI and HbA1c levels, and higher HDL-cholesterol levels.

Busy bees (but not sedentary exercisers) also had lower waist circumferences. Compared to couch potatoes, light movers had only one improvement: higher HDL-cholesterol levels.

What all this shows is not simply the importance of physical activity for health, but that physical activity offsets some of the evils of a high sedentary time. It also suggests that not being sedentary doesn't take you all that far — you still need to exercise.

http://www.eurekalert.org/pub_releases/2016-04/uol-ecs040516.php

Bakrania, K., Edwardson, C. L., Bodicoat, D. H., Esliger, D. W., Gill, J. M. R., Kazi, A., … Yates, T. (2016). Associations of mutually exclusive categories of physical activity and sedentary time with markers of cardiometabolic health in English adults: a cross-sectional analysis of the Health Survey for England. BMC Public Health, 16, 25. http://doi.org/10.1186/s12889-016-2694-9

A small study involving 22 students with depression and 30 mentally healthy students had positive results from a program that combines mental training through meditation and physical training through aerobic exercise. After eight weeks, those with depression showed a nearly 40% reduction in depressive symptoms, and said they did not spend as much time worrying about negative situations taking place in their lives as they did before the study began. There were also changes in brain activity that may reflect better cognitive control.

Interestingly, those in the control group also reported fewer depressive symptoms.

The program involved two sessions a week, with each one having 30 minutes of focused attention meditation followed by 30 minutes of aerobic exercise. They were told that if their thoughts drifted to the past or the future they should refocus on their breathing - enabling those with depression to accept moment-to-moment changes in attention.

http://www.eurekalert.org/pub_releases/2016-02/ru-eam021016.php

Alderman, B. L., Olson, R. L., Brush, C. J., & Shors, T. J. (2016). MAP training: combining meditation and aerobic exercise reduces depression and rumination while enhancing synchronized brain activity. Transl Psychiatry, 6, e726. Retrieved from http://dx.doi.org/10.1038/tp.2015.225

A review of 200 studies on depression and inflammation has concluded that depression and inflammation fuel one another, with inflammation playing a key role in the development of depression in some people, and depression priming greater physiological responses to stress.

Moreover, depression that is caused by chronic inflammation is resistant to traditional therapy methods. However, it is more responsive to activities such as yoga, meditation, omega-3 fatty acids, NSAIDS and exercise.

The review indicates that treatment for depression needs to consider its pathway. The researcher suggests that chronic inflammation is most common in individuals who have experienced stress in their lives, including lower socio-economic status or those who experienced abuse or neglect as children. Other contributing factors are a high-fat diet and high body mass index.

If inflammation is a significant factor, it needs to be treated in tandem with the depression.

http://www.eurekalert.org/pub_releases/2015-12/ru-icf121815.php

Kiecolt-Glaser, J. K., Derry, H. M., & Fagundes, C. P. (2015). Inflammation: Depression Fans the Flames and Feasts on the Heat. American Journal of Psychiatry, 172(11), 1075–1091. http://doi.org/10.1176/appi.ajp.2015.15020152

A ten-year study involving 4,207 older adults (73+) demonstrates that even in this older age group, modest physical activity was associated with a lower risk of cardiovascular disease. Among both men and women in good health:

• those who were more active had significantly lower risk of future heart attacks and stroke
• those who walked faster than three miles per hour had a 50% lower risk than those who walked at a pace of less than two mph (50%, 53%, 50% lower risk of coronary heart disease, stroke and total CVD, respectively)
• those who walked an average of seven blocks per day or more had a similar advantage compared to those who walked up to five blocks per week (36%, 54% and 47% lower risk of CHD, stroke and total CVD, respectively)
• those who engaged in leisure activities such as lawn-mowing, raking, gardening, swimming, biking and hiking, also had a lower risk of CHD, stroke and total CVD, compared to those who did not engage in leisure-time activities

http://www.eurekalert.org/pub_releases/2015-11/tuhs-wfo111915.php

Soares-Miranda, L., Siscovick, D. S., Psaty, B. M., Longstreth, W. T., & Mozaffarian, D. (2015). Physical Activity and Risk of Coronary Heart Disease and Stroke in Older Adults: The Cardiovascular Health Study. Circulation, CIRCULATIONAHA.115.018323. http://doi.org/10.1161/CIRCULATIONAHA.115.018323

Stress, including sleep disturbance, is a major contributor to inflammation in the body. Insomnia is associated with increased risk for depression, medical comorbidities, and mortality.

A study involving 123 older adults (55+) with insomnia randomly assigned them to one of 3 types of classes: cognitive behavioral therapy for insomnia, tai chi, or a sleep seminar (the control condition).

Cognitive behavioral therapy for insomnia reduced insomnia symptoms and levels of the inflammation marker C-reactive protein, and reversed activation of molecular inflammatory signaling pathways. These benefits were maintained for 16 months.

Tai chi also reduced inflammation, reducing the expression of inflammation at the cellular level and reversing activation of inflammatory signaling pathways. It marginally reduced levels of C-reactive protein. Again, these benefits were maintained for 16 months.

Those participants assigned to the sleep seminar classes showed no significant changes in inflammatory markers, as expected.

http://www.eurekalert.org/pub_releases/2015-11/e-bsa110515.php

Irwin, M. R., Olmstead, R., Breen, E. C., Witarama, T., Carrillo, C., Sadeghi, N., … Cole, S. (2015). Cognitive Behavioral Therapy and Tai Chi Reverse Cellular and Genomic Markers of Inflammation in Late-Life Insomnia: A Randomized Controlled Trial. Biological Psychiatry, 78(10), 721–729. http://doi.org/10.1016/j.biopsych.2015.01.010

Your risk of developing type 2 diabetes is about three times greater if someone in your immediate family (parent, sibling) has it. In a study looking at the effects of exercise on this group, it was found that men who have a family member with type 2 diabetes had to expend more energy than a control group, to achieve the same benefits.

The study involved 35 unfit, slightly overweight but completely healthy men aged 30-45 who, for seven months, exercised regularly at a fitness centre. Half of them had relatives with type 2 diabetes, and half did not. (It's perhaps worth noting that 50 men began the study, but didn't continue — these were roughly evenly divided between the two groups.) Three hour-long exercise sessions were available each week, and participants went to 39 sessions on average (the range was large though: 11-107).

Those with family members with diabetes tended to go to the gym more often (group average was 59% more sessions), and this may be due to their increased motivation.

It must be emphasized that both groups lost weight, reduced their waist size, increased their fitness, and showed similar improvements in gene expressions. So exercise was a good idea for both groups. However, statistical analysis indicates that the at-risk group had to do more exercise than the control group to achieve the same benefit. The findings support earlier findings that those with close relatives with type 2 diabetes show smaller physiological changes to exercise, compared to those without such familial links.

http://www.eurekalert.org/pub_releases/2015-10/lu-eig100215.php

Ekman, C., Elgzyri, T., Ström, K., Almgren, P., Parikh, H., Nitert, M. D., … Hansson, O. (2015). Less pronounced response to exercise in healthy relatives to type 2 diabetic subjects compared with controls. Journal of Applied Physiology, 119(9), 953–960. http://doi.org/10.1152/japplphysiol.01067.2014

A review of trials of interventions that sought to reduce sitting time has found the following strategies, among others, were 'promising':

• having sit-stand desks at work
• keeping records of your sitting time
• setting individual goals for limiting sitting time
• having prompts and cues to remind you to stop sitting
• learning about the health benefits of reducing sitting time
• getting feedback on your behavior
• restructuring your physical and social environment to support the behavior changes
• practising the new behavior
• working out how to solve any problems that arise from shifting to less sitting time
• having social support.

The researchers did note that the overall standard of the studies was poor, so we can't yet point to any clear strategy, but these provide a guide for action. They also noted that the more promising interventions involved a greater number of strategies — in other words, to be successful, you need to tackle this behavior change from a number of angles.

http://www.eurekalert.org/pub_releases/2015-09/kcl-sft092115.php

Gardner, B., Smith, L., Lorencatto, F., Hamer, M., & Biddle, S. J. (2016). How to reduce sitting time? A review of behaviour change strategies used in sedentary behaviour reduction interventions among adults. Health Psychology Review, 10(1), 89–112. http://doi.org/10.1080/17437199.2015.1082146

In a study involving 52 sedentary, overweight, middle-aged men and women (aged 45-65), both exercise and calorie restriction had positive — and equal — effects on insulin sensitivity, but a combination of both had twice as much benefit for glucoregulation as either single approach. All three programs were designed to achieve about the same amount of weight loss (6-8%).

The study also indicated that both exercise and calorie restriction improve regulation of glucose levels through weight loss, but also through mechanisms that are independent of weight loss.

What all this suggests is that, even if you're maintaining a healthy weight, how much you eat, and whether you exercise, are factors that have health implications.

http://www.eurekalert.org/pub_releases/2015-05/slu-ido050615.php

Weiss, E. P., Albert, S. G., Reeds, D. N., Kress, K. S., Ezekiel, U. R., McDaniel, J. L., … Villareal, D. T. (2015). Calorie Restriction and Matched Weight Loss From Exercise: Independent and Additive Effects on Glucoregulation and the Incretin System in Overweight Women and Men. Diabetes Care, 38(7), 1253–1262. http://doi.org/10.2337/dc14-2913

One big issue for which there is as yet no clear answer, is the question of whether it's the intensity or the amount of exercise which is more important.

One study involving 300 obese adults aimed to test this in a 6-month trial comparing those who maintained their usual activity level, those who did a low amount (around 30 minutes) of low-intensity exercise, those who did a high amount (around an hour) of low-intensity exercise, and those who did around 40 minutes of high-intensity exercise. All had five exercise sessions every week.

After 24 weeks of this, all the exercise groups showed smaller mean waist circumference and greater mean weight loss, compared to the control group, but there was no difference between the exercise groups in these measures. However, only the high-high group had lower 2-hour glucose levels than the controls, and only the two groups who did a higher amount of exercise had better insulin sensitivity.

Ross R et al. Effects of exercise amount and intensity on abdominal obesity and glucose tolerance in obese adults: A randomized trial. Ann Intern Med 2015 Mar 3; 162:325. (http://dx.doi.org/10.7326/M14-1189)