The brain waves during stage 1 NREM sleep transition from daytime patterns to nighttime patterns. Stage 2 NREM sleep is when most people would consider themselves to be "asleep." The heart rate and ...

It lasts for just 1–5 minutes. Stage 2: Slightly deeper, this phase lasts around 25 minutes. The body relaxes further. Stage 3: This is the deepest stage of sleep. Heart rate, breathing, and brain ...

That means stages 1 and 2, which are sometimes called “light ... It has the slowest brain waves, so it’s sometimes called “slow wave sleep.” It’s hard to wake someone up from this ...

While the verdict on its cause is not clear, Alzheimer's is thought to be caused by a combination of factors, including ...