We all know the amount of sleep we're supposed to be getting. And we all probably feel guilty about the fact that we're not going to get there, no matter how many screen-less, caffeine-less hours we spend trying. In fact, about 40% of us are officially sleep-deprived . But, a new study looking at sleep habits among pre-industrial societies found that our forebears most likely weren't getting their eight hours, either.For the study , published online this week in Current Biology, researchers monitored the sleeping patterns of three remote hunter-gatherer societies (in Tanzania, Bolivia, and Namibia) — people who have lifestyles that are presumably similar to those of our ancestors.Using activity trackers ("souped-up, medical-grade Fitbit[s] for sleep," according to The Washington Post ), the team kept track of when participants went to sleep, woke up, and what they did in between for up to 28 days. And, for one group, the researchers also tracked how participants' sleep habits changed between summer and winter months.Results showed that, despite not using technology like us "modern" humans, the participants didn't get much more sleep than we do. On average, they slept between 5.7 and 7.1 hours per night (much less than the seven to nine hours that are recommended for adults ), tended to stay awake about three hours after sunset, and woke up before sunrise. They also reported no ill health effects due to their sleep schedules, and they rarely took naps (especially rarely in the winter). All three groups — the subjects in Tanzania, Bolivia, and Namibia — showed very similar sleep patterns, despite their geographical separation.We commonly blame our less-than-stellar sleep records on our crazy modern lives and the technology and stress that go with them. While that makes sense, these results suggest it might not actually be all that true. And perhaps our sleep standards are a little higher than they need to be — especially because anxiety about getting enough shut-eye and the fear that it's not going to happen can both make insomnia worse That said, the study also mentioned that habits we often discuss when it comes to getting more ZZZs are right on the money: getting light first thing in the morning, keeping the temperature cool in your bedroom, and waking up at the same time every day all seem to help. But if you feel fine after six hours, you can stop feeling guilty about staring at your phone until midnight. Let's all just take it easy, huh?