fitness · health

Chairs are evil (once again)

Yet one more research article adds nails to the coffin of an idea. The soon-to-be-buried idea is that exercising vigorously for an hour a day can offset the metabolic damage to your health caused by sitting.

This one is of special interest to cyclists like me who like to spend our days riding hard, followed by flopping at the desk. (I’m reformed now. I have a standing desk. But if it weren’t for back problems caused by sitting, I’d still rather ride hard then flop.)

Called, “Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable.” You can read the piece here.

Here’s some highlights from the abstract:

“Epidemiological studies suggest that excessive sitting time is associated with increased health risk, independent of the performance of exercise. We hypothesized that a daily bout of exercise cannot compensate the negative effects of inactivity during the rest of the day on insulin sensitivity and plasma lipids.”

And their method and findings:

“Eighteen healthy subjects, age 21±2 year, BMI 22.6±2.6 kgm−2 followed randomly three physical activity regimes for four days. Participants were instructed to sit 14 hr/day (sitting regime); to sit 13 hr/day and to substitute 1 hr of sitting with vigorous exercise 1 hr (exercise regime); to substitute 6 hrs sitting with 4 hr walking and 2 hr standing (minimal intensity physical activity (PA) regime). The sitting and exercise regime had comparable numbers of sitting hours; the exercise and minimal intensity PA regime had the same daily energy expenditure. PA was assessed continuously by an activity monitor (ActivPAL) and a diary. Measurements of insulin sensitivity (oral glucose tolerance test, OGTT) and plasma lipids were performed in the fasting state, the morning after the 4 days of each regime. In the sitting regime, daily energy expenditure was about 500 kcal lower than in both other regimes. Area under the curve for insulin during OGTT was significantly lower after the minimal intensity PA regime compared to both sitting and exercise regimes 6727.3±4329.4 vs 7752.0±3014.4 and 8320.4±5383.7 mU•min/ml, respectively. Triglycerides, non-HDL cholesterol and apolipoprotein B plasma levels improved significantly in the minimal intensity PA regime compared to sitting and showed non-significant trends for improvement compared to exercise.”

Conclusions?

“One hour of daily physical exercise cannot compensate the negative effects of inactivity on insulin level and plasma lipids if the rest of the day is spent sitting. Reducing inactivity by increasing the time spent walking/standing is more effective than one hour of physical exercise, when energy expenditure is kept constant.”

I’d be curious about a group who did a mix–some high intensity exercise, followed by some standing and walking, rather than sitting. I’d like to know if they fared even better. Doesn’t matter really. I’d keep doing the high intensity for performance improving reasons. The take home lesson for me is–yell it loudly one more time–GET UP OUT OF THAT CHAIR!!!

We’ve written a lot here about the evils of sitting. Let me remind you!

To complete the picture here’s an evil chair, image from Deviant Art, by Blank Mange, http://fc02.deviantart.net.

image

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