The US National Transportation Safety Board (NTSB) has warned of the risk of “sleep inertia”, that short-lived feeling of grogginess felt immediately after waking up. The NTSB said that sleep inertia usually lasted for about 30 minutes after waking, and could last longer if a person was suffering...
https://insurancemarinenews.com/insurance-marine-news/ntsb-warns-of-sleep-inertia-dangers/