Health

A small study involving 11 non-obese, healthy men aged 20-35, has found that blood flow in leg arteries is significantly impaired after three hours of sitting, but not if they walk for five minutes every hour.

When people sit, slack muscles do not contract to effectively pump blood to the heart. Blood can pool in the legs and affect the endothelial function of arteries, or the ability of blood vessels to expand from increased blood flow. Impaired endothelial function is an early marker of cardiovascular disease.

In the study, participants sat for three hours without moving their legs, while the functionality of the femoral artery was taken at baseline and every hour. This showed that the expansion of the femoral artery as a result of increased blood flow was impaired by as much as 50% after just one hour.

In another session, they again sat for three hours, but also walked on a treadmill for 5 minutes at a speed of 2 mph at the 30-minute mark, 1.5-hour mark and 2.5-hour mark. In this case, arterial function stayed the same throughout the session.

http://www.eurekalert.org/pub_releases/2014-09/iu-tsw090514.php

Thosar, S. S., Bielko, S. L., Mather, K. J., Johnston, J. D., & Wallace, J. P. (2015). Effect of Prolonged Sitting and Breaks in Sitting Time on Endothelial Function: Medicine & Science in Sports & Exercise, 47(4), 843–849. http://doi.org/10.1249/MSS.0000000000000479

A Czech study involving 146 people with mild to moderate risk of cardiovascular disease has found that moderate wine drinking was only protective in people who exercised.

Participants were randomly assigned to one year of moderate consumption of red wine (Pinot Noir) or white wine (Chardonnay-Pinot) from the same year and wine region of the Czech Republic. They had to keep a logbook on their consumption of wine and other alcoholic beverages, medication use, and amount and type of exercise. They were required to return the corks from the wine bottles to confirm that they had drank the wine rather than sold it.

The study was looking for a rise in HDL cholesterol, indicating a protective effect against cardiovascular disease. However, there was no change in HDL cholesterol levels by the end of the study in either the red or white wine groups. Nor did it appreciably affect blood glucose, triglycerides, or levels of inflammatory markers like C-reactive protein, although LDL cholesterol was lower in both groups while total cholesterol was lower only in the red wine group.

However, those participants who engaged in regular exercise at least twice a week did show an increase in HDL cholesterol, as well as a decrease in LDL and total cholesterol. This occurred in both red and white wine groups.

Of course, the study didn't include a control group of people engaging in regular exercise who didn't drink, so all we can really say (and it's certainly worth saying) is that moderate wine drinking doesn't seem to help protect against cardiovascular disease, and that despite all the hype around red wine, with its greater antioxidants and resveratol, there's no evidence it's any healthier than white wine.

http://www.eurekalert.org/pub_releases/2014-08/esoc-wop082614.php

http://www.theatlantic.com/health/archive/2014/09/working-with-the-wine-not-against-it/379504/

Taborsky M, Ostadal P, Petrek M. A pilot randomized trial comparing long-term effects of red and white wines on biomarkers of atherosclerosis (in vino veritas: IVV trial). Bratisl Lek Listy. 2012;113(3):156-158.

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)

A study looking at the workout habits of more than 55,000 individuals for 15 years has concluded that running can reduce a person’s all-cause mortality rate by 30% and cardiovascular mortality rate by 45%. This equated to a difference of about three years of life.

But the really exciting news is that people who ran less than an hour each week showed the same mortality benefits compared to those who ran more than three hours in each week. Note that this is more about running, say, ten minutes every day, than only running once a week for a longer time! You don't have to run fast, either. Those running more slowly (< 6 miles/hour) got the same benefits.

Not running had about the same negative effect on life expectancy as having hypertension.

Around 24% of the participants did some running. The average age was 44.

http://www.futurity.org/even-short-slow-running-can-extend-lifespan/

Lee D, Pate RR, Lavie CJ, Sui X, Church TS, Blair SN. Leisure-Time Running Reduces All-Cause and Cardiovascular Mortality Risk. J Am Coll Cardiol. 2014;64(5):472-481. doi:10.1016/j.jacc.2014.04.058.

A Canadian study involving 129 sedentary adults (aged 18-64) found that they tended to underestimate how hard they should be working to achieve levels of moderate and vigorous intensity while moving on a treadmill. This is despite being given commonly used exercise intensity descriptors.

The finding suggests that, while considerable thought has been given in developing physical activity guidelines, most people don't understand them well enough to use them.

For adults to achieve a moderate intensity, their heart rates should be within the range of 64-76% of their maximum heart rate and between 77-83% for vigorous intensity, according to the Canadian and global physical activity guidelines.

http://www.eurekalert.org/pub_releases/2014-06/yu-moe061614.php

Canning KL, Brown RE, Jamnik VK, Salmon A, Ardern CI, Kuk JL (2014) Individuals Underestimate Moderate and Vigorous Intensity Physical Activity. PLoS ONE 9(5): e97927. doi:10.1371/journal.pone.0097927

A Finnish study involving 2,570 middle-aged men (42-60) has found that men sleeping less than 6 hours or more than 10 hours suffer from low-grade inflammation (indicated by levels of C-reactive protein) more often than persons sleeping 7-8 hours per night. Additionally, the serum levels of zinc, and the zinc/copper ration, were lowest in those sleeping less than 6 hours, while copper levels were highest in those sleeping more than 10 hours.

It has been suggested that high serum copper concentration is linked to pro-oxidative stress, found in many chronic diseases.

http://www.eurekalert.org/pub_releases/2015-09/uoef-lsa091415.php

Luojus, M. K., Lehto, S. M., Tolmunen, T., Elomaa, A.-P., & Kauhanen, J. (2015). Serum copper, zinc and high-sensitivity C-reactive protein in short and long sleep duration in ageing men. Journal of Trace Elements in Medicine and Biology, 32, 177–182. http://doi.org/10.1016/j.jtemb.2015.07.008

A small clinical trial involving 49 older adults (average age 66) found that the group who were given a standardized mindfulness meditation program had greater improvement in sleep score than the group given a sleep hygiene education program. They also showed greater improvement on secondary measures of insomnia symptoms, depression symptoms, fatigue interference and fatigue severity. However, differences between the groups were not seen for anxiety, stress or inflammatory signaling, the last of which declined in both groups.

http://www.eurekalert.org/pub_releases/2015-02/tjnj-mma021215.php

Black DS, O’Reilly GA, Olmstead R, Breen EC, Irwin MR. Mindfulness Meditation and Improvement in Sleep Quality and Daytime Impairment Among Older Adults With Sleep Disturbances: A Randomized Clinical Trial. JAMA Intern Med. 2015;175(4):494-501. doi:10.1001/jamainternmed.2014.8081.

A small study involving 15 adults with moderate-to-severe obstructive sleep apnea and 19 controls with mild or no sleep apnea has found that predicted peak oxygen uptake (VO2), a measure of aerobic physical fitness, was significantly lower in those people with moderate to severe obstructive sleep apnea. Moreover, the number of times a person stopped breathing, for 10-seconds or more, per hour of sleep, predicted 16% of the variability observed in the group's peak VO2.

People who suffer from apnea are more likely to be obese and thus would be expected to be less fit as well, but even compared to people with similar BMI, the apnea patients had a reduced aerobic fitness. It's suggested that the sleep apnea itself causes structural changes in muscle that contributes to exercise problems.

VO2 max measurements may be an early marker for those who are at higher risk of stroke and heart attack

http://www.eurekalert.org/pub_releases/2014-12/aaos-sls120114.php

http://www.eurekalert.org/pub_releases/2014-11/uoc--sal112414.php

Beitler JR, Awad KM, Bakker JP, Edwards BA, DeYoung P, Djonlagic I, Forman DE, Quan SF, Malhotra A. Obstructive sleep apnea is associated with impaired exercise capacity: a cross-sectional study. J Clin Sleep Med 2014;10(11):1199-1204.

A study involving 302 older women (mean age 82) has found that those with moderate to severe sleep apnea were at twice the risk of having problems in performing basic functions associated with independent living.

http://www.eurekalert.org/pub_releases/2014-11/jhub-oww111214.php

Spira, A. P., Stone, K. L., Rebok, G. W., Punjabi, N. M., Redline, S., Ancoli-Israel, S., & Yaffe, K. (2014). Sleep-Disordered Breathing and Functional Decline in Older Women. Journal of the American Geriatrics Society, 62(11), 2040–2046. http://doi.org/10.1111/jgs.13108

A study involving 49 office workers, of whom 27 worked in windowless workplaces and 22 in workplaces with windows, has found that those exposed to natural light slept better, and were also more active.

Employees with windows in the workplace received 173% more white light exposure during work hours and slept an average of 46 minutes more each night.

Workers without windows had lower scores on quality of life measures related to physical problems and vitality, as well as poorer outcomes on measures of overall sleep quality and sleep disturbances.

http://www.futurity.org/windows-workers-sleep-health-745022/

Boubekri M, Cheung IN, Reid KJ, Wang CH, Zee PC. Impact of windows and daylight exposure on overall health and sleep quality of office workers: a case-control pilot study. J Clin Sleep Med 2014;10(6):603-611.