Does Exercise Effectively Treat Depression?

Testing the clinical benefits of exercise is no small task. While placebos can be given in drug trials, there is no such equivalent for physical activity. A new study has raised controversy over its methods. 

What's the Latest Development?

A controversial study has emerged over whether exercise is an effective treatment for depression, prompting an examination into claims about how physical activity affects mental illnesses. At the heart of the controversy is the fact that testing the effects of exercise are quite difficult given the gold standard of medical trials, i.e. a controlled experiment in which subjects do not know whether they are receiving the actual treatment or a placebo. With exercise, it is difficult to have unbiased control subjects because, unlike swallowing a placebo, treatment involves very active participation.

What's the Big Idea?

In determining whether exercise is an effective way to treat depression, it may be more helpful to turn to meta analyses which take stock of multiple studies at once. The Cochrane collaboration, a not-for-profit organisation that creates systematic reviews of health studies, has conducted such an analysis, finding that "on the whole, exercise has been shown to have some benefits for those with depression, but when only the very best-designed studies were included, this effect was very small." Because exercise releases feel-good chemicals in the body known as endorphins, it is known to be a mood enhancer, but the complexities of clinical depression are not so easily resolved. 

Photo credit:

A dark matter hurricane is crashing into Earth

Giving our solar system a "slap in the face."

Surprising Science
  • A stream of galactic debris is hurtling at us, pulling dark matter along with it
  • It's traveling so quickly it's been described as a hurricane of dark matter
  • Scientists are excited to set their particle detectors at the onslffaught
Keep reading Show less

We are heading for a New Cretaceous, not for a new normal

The climate change we're witnessing is more dramatic than we might think.

Image credit: NASA Goddard Space Flight Center from Greenbelt, MD, USA
Surprising Science

A lazy buzz phrase – 'Is this the new normal?' – has been doing the rounds as extreme climate events have been piling up over the past year. To which the riposte should be: it's worse than that – we're on the road to even more frequent, more extreme events than we saw this year.

Keep reading Show less

New study reveals what time we burn the most calories

Once again, our circadian rhythm points the way.

Photo: Victor Freitas / Unsplash
Surprising Science
  • Seven individuals were locked inside a windowless, internetless room for 37 days.
  • While at rest, they burned 130 more calories at 5 p.m. than at 5 a.m.
  • Morning time again shown not to be the best time to eat.
Keep reading Show less