A sedentary life (of the kind you probably live if you’re reading this – although not necessarily) leads to higher levels of testosterone and oestrogen, which might sound good to some people, but which can increase risks of cancers. By contrast, the Hadza – who do around two hours of moderate and vigorous physical activity every day, many times more than typical people in the UK and the USA – have morning salivary testosterone concentrations that are roughly half those of western populations.
