The Australian government currently recommends 2.5 hours of physical activity per week, with a caveat that says you should try to be active every day.
This is a rather open ended recommendation; if you go to the gym for an hour and a half two days a week are you done? Should you just relax for the rest of the week?
According to a study recently published in the Scandinavian Journal of Medicine and Science in Sports, the answer to how much exercise you should do a week is a little bit everyday, specifically when it comes to muscular strength.
The team of researchers based at Edith Cowan University studied the effect of a certain number of eccentric contractions over a four week period. There were three groups, one which did 30 contractions (bicep curls specifically) in one session, another that did six contractions in one session, and the final group which did six contractions five days per week.
In the group that did six contractions once a week for four weeks no change in muscular strength or size was measurable. Interestingly the group that was tasked with doing thirty contractions once a week for four weeks saw a 5.8% increase in muscular size but no significant increase in muscular strength.
The stand out group was the more consistent, lower rep 6×5 days per week group. The results showed that this group not only had an 11.5% increase in muscular strength but also a 4.4% increase in muscular size.
The researchers suggest that this means that a consistent amount of exercise is more beneficial than one larger dose.
With that being said, this study only measured the effect of weight training on muscle gain, not cardiovascular fitness and other types of exercise. It also appears that to achieve muscular hypertrophy load and intensity is important as shown in the 30 reps per week group.
The short-term nature of this study and the limited exercise limit the reach of its impact, however, the results do indicate that a little everyday may well be more beneficial than a lot once every week.
Riku Yoshida, Shigeru Sato, Kazuki Kasahara, Yuta Murakami, Fu Murakoshi, Kodai Aizawa, Ryoma Koizumi, Kazunori Nosaka, Masatoshi Nakamura. Greater effects by performing a small number of eccentric contractions daily than a larger number of them once a week. Scandinavian Journal of Medicine & Science in Sports, 2022; DOI: 10.1111/sms.14220