There are people claiming all sorts of things here without much proof. The amount of actual sleep can be as low as 3-4 hours for 8-9 hours spent in bed, and there is no way of knowing how much you sleep without some sort of investigation using a reliable device.<p>To really know what&#x27;s happening with your sleep, you need polysomnography. An actual sleep study.<p>The second best option are some of the consumer-grade ballistocardiography devices - the &quot;under mattress&quot; alternative to wearables.<p>I have been tracking my sleep and fixing problems with it using the Beddit device. As a gadget and product, I rate it 2 or 3 out of 5 - I&#x27;d love it to be more polished. But considering its potentially life changing value and its technical merits, a highly recommended purchase.<p>Even just the resting heart rate reading and HRV data are worth the price.<p>My 2 months of data are so far fairly inconclusive and pending deeper statistical analysis. There are many variables at play, so recognizing and documenting them takes time and effort and is error prone. The most confident recommendations are not drinking alcohol, earplugs (fairly noisy environment), and melatonin. Even with these, I have been unable to consistently get more than an average of 5 hours (±1) of actual total sleep during 7-9 hours of time spent in bed. The time spent awake isn&#x27;t something I experience or remember. This hasn&#x27;t been noticeable to me despite long days and an active athletic lifestyle including goal-oriented recreational endurance and strength training.