To nap or not to nap?

The concept of sleep inertia has presented it's self to me a couple of times in the past few weeks. Once when I mentioned to a sleep scientist that I am like 'a bear with a sore head' if I have a day time nap (the cause most likely sleep inertia). Another time was when I was talking to an emergency services worker, discussing the pro's and con's of napping during night shift. I also saw a promo for a morning show that was airing a segment on 'Napping the key to health and happiness' but I missed watching this.

So what are the pro's and con's of napping?
One of the cons can be sleep inertia. This is especially relevant to emergency services workers who may take naps during night shift. Sleep inertia is bascially a temporary state of lowered arousal occurring immediately after awakening from sleep and producing a temporary decrease in cognitive performance. Sleep inertia can be influenced by factors such as the duration of prior sleep, and the sleep stage prior to awakening. Abrupt awakening during a slow wave sleep (stage 3 and 4) episode produces more sleep inertia than awakening in stage 1 or 2, REM sleep being intermediate. Studies have demonstrated that sleep inertia can last from 1 min to 4 h but usually last around 15 to 30min. The practical implications for those working in our emergency service is that being woken to respond to an immediate emergency gives them no time to recover from the effects of sleep inertia. Being awaken for deep NREM sleep has been shown to decrease reaction time which is highly dangerous for those driving (fire and ambulance crews) and health professionals responding to an emergency.

Conversely, the benefits of a power nap (15 to 30 minutes) have been well document as a way to ward off fatigue and improve cognitive function. There is still a level of sleep inertia but this can be minimised by a short nap (stage 1&2) and having adequate time to 'wake up' after this nap before preforming any important tasks.

Health and Safety recommendations such as these from the Queensland Government reinforce this with recommendations sleep inertia can be minimised for workers who are on-call for emergencies by the following steps;

• Minimising naps taken at work that exceed 40 minutes; and
• Planning for recovery times of up to 30 minutes for workers who may be subject to sleep inertia, before they are to perform hazardous tasks.

Jessica