A bracing coastal walk has long been regarded as a perfect way to blow away the cobwebs but a new study suggests it can also result in almost an hour of extra sleep.

The study found that people sleep on average for 47 minutes longer the night after a decent seaside hike while those who go for an inland walk of a similar length sleep only for an additional 12 minutes.

According to the study, a coastal walk also provokes more thoughts of family and childhood and provides greater opportunity for introspection and reflective thought compared with a landlocked stroll.

Environmental psychologist Eleanor Ratcliffe, who carried out the research for the National Trust, said: “It’s clear there is something really special about the coast that can allow people to boost their mood, relax and sleep.”

About 100 walkers aged 21-82 took part in the study, walking an average of seven miles each. Half walked coastal paths in places such as Devon, Dorset and Wales. The others went on inland walks, taking in hills, heathland and parks.

Both groups reported they felt happier, calmer, more alert and slept better and longer after their walks.

But Ratcliffe, who herself has happy memories of childhood seaside walks and cycle rides at Aldeburgh in Suffolk, found that coastal walkers experienced a “significantly” longer night’s sleep than the inland group.

The results may not be wholly surprising. After all, the number of sleep aids on the market connected to the sea, such as CDs featuring ocean sounds, suggests possible links between the coast and conditions suitable for sleep.

But why the coastal walkers slept for so much longer is a puzzle. Ratcliffe suggested that the seasiders were more likely to associate the walk with a holiday experience. She said: “Given relationships between restorative environments and a sense of escape or ‘being away’ from daily life, it may be that coastal walkers felt more able to relax and let go in these environments due to their associations with holidays, with potential effects on sleep length.”

What people thought about during their walks also varied depending on if they were by the sea or not. Walking by the sea triggered memories associated with people close to the walker, such as parents, children or other family members and their own childhoods. Ratcliffe said the lack of much to see – apart from the water – could be one reason for more internal reflection.

Inland walkers were less likely to focus on internal thoughts and commented on social aspects of the walk such as company and conversation far more than coastal walkers.

The research was commissioned as part of the National Trust’s annual Great British Walk campaign.