Headache, nausea, irritability, concentration problems, fatigue and other ailments are common symptoms of the hangover suffered by anyone who has had a few too many alcoholic beverages. Recently, Northern Territory based thermal physiologist, Dr Matt Brearley introduced the term “heat hangover” to describe the similar symptoms suffered by those who had not drunk any alcohol but had pushed themselves too hard working in the heat.
He described a post-shift headache and nausea as common issues among those working in the tropics or underground mines.
He said there is also anecdotal evidence of reduced social interaction and tolerance of others as a result of the heat hangover which has historically been known in the tropics as ‘mango madness’.
According to Brearley, the heat hangover is likely to compromise the safety of staff as workers operate at a fraction of their physical and mental capacity.
Milder consequences are likely to include lower productivity as the impact of physical work and body heat storage causes employees to pace their efforts during subsequent work shifts.
Brearley writes on his website that the heat hangover also impacts the quality of downtime between shifts with more severe cases causing workers to skip dinner and go straight to bed. He suggests that the heat hangover is the leading cause of staff turnover in the tropics.
Research has shown the heat hangover is hard to predict. Brearley was part of a team that examined 16 urban search and rescue personnel during a 24 hour exercise in hot conditions.
Seven of the 16 monitored staff reported to the onsite medical team with symptoms of a heat hangover including nausea (7), headache (7) and vomiting (1) along with high core body temperatures, despite testing in the two hours prior showing no symptoms of heat related illness or heat stress such as increased core body temperature and heart rate.
He said it appeared that substantial body heat storage, heart rate and sweat rates during the initial four hours of the study, followed by moderate body heat storage during subsequent shifts promoted the heat hangover symptoms.
Brearley concluded that the heat hangover is difficult to predict and depends on an individual’s physical fitness and heat acclimatisation status, recent illness and sleep quality, among other factors – with more research required.
He suggested that heat stress management strategies are essential in reducing excess body heat storage and minimising the prevalence of the heat hangover and its associated problems.