According to news this week, one way might be to become very sceptical about the value of your fitness tracker. Stanford University researchers have shown that Fitbit et al are pants.

That’s not strictly true. The trackers are pretty accurate when it comes to measuring heart rate, which is no big surprise. It’s real easy to do that. Where they fall down is on calculating the calories you’ve burned*.

You’d expect a bit of inaccuracy and variation here, because it’s pretty difficult to measure in a lab, let alone when you’re running through the countryside or risking your life by cycling in Hoxton. I say a bit. Even the best of the trackers was out by a substantial 23%. That figure pales into insignificance when you look at the worst. This will mislead you to the tune of 93%. This means the fry-up you have just tried to work off hasn’t been worked off at all.

Then some rather unsettling and somewhat unsettling news about meditation. There’s an increasing (and lucrative) market for meditative techniques being taught to treat a variety of disease conditions. Addiction, stress, anxiety, depression, even analgesia. There are some pretty robust studies to show efficacy here, but as far as I can ascertain no placebo-controlled trials, which are the gold standard.

The worrisome aspect of the field is this. People report the benefits, but not the downside. In some people, meditation can actually increase levels of anxiety and even lead to panic attacks. The adverse effects have long been documented in the Buddhist texts that form the basis of meditation, but get hardly a mention in modern studies. Also no mention of hypersensitivity to light and sound, insomnia, and bodily tics. You have been warned.

On a more cheerful note, you can reduce the risk of drowning when you fall into cold water. Cold water shock will make you gasp quickly, and the sense of panic will make you try to swim for it. Don’t. Give yourself a coupe of minutes of floating before you strike out for the shore. Apparently this gives your body time to acclimatise. It does of course require presence of mind and exceptional levels of self-control, but hey ho.

*Bizarrely there have been reports of fitness freaks trying to prolong sex not to increase anybody’s pleasure, but to increase calorie burn. If your partner actually consults a tracker mid-shag, I reckon the calorie burn stops right there.