Some people simply don't have a head for heights, but the real reason you start to feel wobbly near a drop may have more to do with your feet. Scientists have found that standing near a drop triggers the nervous system to 'turn up' the sensation in your soles. That process is the reason you might feel an unusual buzzing, tingling, or even sense of heaviness in your feet near a drop.
How the Brain Responds to Heights
According to Professor Michelle Spear, an expert on anatomy from the University of Bristol, this could explain why some people handle heights better than others. When we get near a drop, our brain starts to 'upregulate' the inputs coming from the feet. For some people, this works in the background to improve balance, while others feel a distracting level of awareness.
Professor Spear told the Daily Mail: 'The brain appears to “turn up the volume” on sensory signals involved in posture and foot placement. What is usually background processing can therefore become consciously noticeable.'
Feeling scared of heights is exceptionally common, with around a quarter of people experiencing some level of discomfort. However, studies have also shown that most people show measurable changes in balance and posture when they come close to a drop.
The Role of the Nervous System
The nervous system is constantly processing huge amounts of sensory information, but most of it never reaches conscious awareness. To prevent us from being overwhelmed, a large part of this data is filtered out or tuned down. However, when the central nervous system needs to, it can turn up the volume on some of these channels.
Professor Spear says: 'The nervous system appears to respond to height by increasing vigilance around balance and foot placement. Sensory input from the feet becomes more important, posture stiffens slightly, and movements become more cautious and deliberate.'
The soles of the feet are covered in a dense layer of specialised receptors that track changes in touch, vibration, and weight distribution. As our primary point of contact with the ground, this rich source of sensory information is absolutely essential to maintaining balance and posture. For the most part, these sensors work quietly in the background, helping us walk or shift our weight without needing to consciously think it through.
Evolutionary Adaptation
When we come near a large drop, however, the risk of falling is so much higher that the body starts paying more attention to those signals. Professor Spear says this could be an adaptation that arose in our evolutionary past, helping our ancestors to avoid a fatal tumble. She says: 'Humans evolved in environments where falls carried significant risk, whether moving across uneven ground, climbing, or navigating rocky and elevated terrain. From an evolutionary perspective, a system that encouraged careful movement near a drop would have been advantageous.'
These changes are automatic, taking place in the background whether we want them to or not, but some people seem to notice the change much more than others. Greater awareness of pressure and balance could be beneficial for climbing, and experienced climbers often develop a highly attuned sense for weight distribution. However, too much sensory awareness can become distracting or provoke anxiety, which gets in the way of fluid movement.
Symptoms and Sensations
Professor Spear says that the 'upregulated' signals from the feet can feel like a buzzing or tingling in the soles. Other people report a sense of heaviness, as though their feet are being drawn to the ground, while others feel a sensation of unsteadiness and the need to hold still. For some, the feeling manifests as a reluctance to move forward or get any closer to the edge.
This is a distinct issue to vertigo, which arises from a disturbance in the inner ear that creates a false sense of movement. Professor Spear says the difference may lie in how people process sensory information. She says: 'Some individuals appear more sensitive to subtle proprioceptive and tactile feedback, while others filter these signals more effectively below the level of conscious awareness. Attention also plays a role: once someone notices the sensation, the brain becomes more likely to detect it again in future.'
Common Symptoms of Fear of Heights
- Queasiness
- Inner agitation
- Instability of stance and gait
- To-and-fro vertigo
- Weakness in the knees
- Palpitations
- Trembling
- Light-headedness
- Sudden sweating
Source: Hans-Peter Kapfhammer, et al., (2015)
