Working out alone risks hallucinations

• Experts believe exercise could produce a version of the ‘third man’ effect

People who go diving and climbing, and even those who cycle, run or hike for long distances, are at risk of being ‘haunted’ by imaginary presences, a study suggests.

That may be a guardian angel-type figure, helping them to stay the course, or the apparition of a dead loved one.

Experts believe exercise, especially when it has an endurance element or is done alone, could produce a version of the ‘third man’ effect described by explorer and Kildare native Ernest Shackleton, who famously hallucinated an extra member of his team guiding him on South Georgia Island.

Researchers led by Durham University were able to find 84 participants in sport who had experienced an unknown presence, after putting out an appeal to organisations including UK Caving, the British Mountaineering Council and Cornish adventure sports firm FreediveUK.

Almost one in five people said they had felt like they were being watched or followed, with almost 30 per cent saying the presence they sensed was someone they knew or had known in the past.

Almost 28 per cent found the presence comforting, with 19% finding it frightening.

Dr Ben Alderson-Day, who led the study from Durham University, described the phenomenon in people such as mountaineers and climbers at Cheltenham Science Festival, stating: ‘Right at the brink, suddenly they feel like there is a ghostly companion with them, just for that period, and somehow they get through (the physical challenge).’

Weekend warriors is the nickname for office workers who take part in strenuous exercise at weekends to make up for their largely sedentary week.

Speaking after the talk, Dr Alderson-Day said: ‘Weekend warriors who are doing extreme exercise, and trying to push through a physical barrier to complete it, should be aware that they may start to feel a presence that isn’t there.

‘The explanation is thought to be that when you are pushing yourself, and when there is not much sensory input, like in a cave, underwater or on a mountain, you lose your internal sense of where your body is positioned in physical space, so start to sense your own body outside of yourself and believe it is someone else.’

He added: ‘It seems to be more common in people doing these sports alone, and in those with an endurance element, but it can also happen during something like a marathon.’

The study, published in the journal Psychological Medicine, quotes one man who takes part in caving describing an imaginary presence as ‘the feeling that someone is watching me, not necessarily for my benefit either’. 

He added: ‘[It occurs] in an old mine, usually when I’m alone at the rear of a party.’