You know the wall sit. Back flat against the wall, slide down like you're sitting on an invisible chair, and hold until your legs start writing complaint letters. It's the exercise PE teachers loved. Turns out it may also be one of the easiest ways to look after your blood pressure.
The study
Researchers led by Harry Swift ran a trial with 100 adults, average age 37. Their blood pressure was on the high side of normal, a top number between 120 and 140, but nobody had been diagnosed with hypertension. None of them did regular structured exercise, and none took blood pressure pills.
They were split into five groups. One did nothing, as the comparison. The other four did wall sits at home, three times a week, for four weeks.
Each session was short: four holds, with two minutes of sitting down to rest between them. Holds were about one to two minutes each. The whole thing fits between the kettle boiling and the toast popping. Well, almost.
The results
After four weeks, every wall-sit group had lower blood pressure than the group that did nothing. On average, the top number was about 9.5 points lower than the comparison group.
Then came the interesting part. For the next four weeks, one group kept going three times a week, one dropped to twice, one to once, and one stopped completely.
The three-times-a-week group did best: their top number ended up 13.7 points lower than where they started. Twice a week, about 7 points lower. Once a week, about 6.6 points lower. And the group that stopped? Their gains faded, and they ended up no different from the people who never did anything.
"Even minimal engagement can help maintain significant benefits," the authors wrote.
Why it might work
Holding a muscle tight squeezes the blood vessels. When you let go, blood rushes back in, and over time the vessels seem to learn to relax more easily. The three-times group also kept improvements in how much the blood vessels resist the flow and in heart rate variability, a sign of a healthy heart rhythm.
The small print
This was a short trial: four weeks of training, then four weeks of keeping it up. Longer studies are needed to know whether once a week still works after months or years. And the people in it were fairly young and didn't have hypertension.
So, the channel's motto stands: you are not a doctor. If you already have high blood pressure, take medication, or have knee or heart problems, ask your doctor before starting. Wall sits are not a replacement for your pills.
What it means for you
If you've been looking for an exercise that needs no gym, no kit and no Lycra, this is it. Back to the wall, knees bent to roughly a right angle, feet a little in front of you. Hold, rest, repeat four times. Keep breathing normally.
Three times a week is the gold standard. But if life gets busy, the message from this study is lovely: once a week is much better than nothing. The only thing that really doesn't work is stopping.
Your legs may hate you on day one. Your heart, apparently, will send a thank-you card.