Why It's Normal to Feel Grumpy in the Heat

Researchers have proven that hot weather causes bad moods (Photo: Getty)

Think back to the last time you felt insanely hot. It may have been on the beach. It may have been at work. It was probably last night, as it’s not easy to sleep during a heatwave.

One thing’s for sure: You probably felt a little irritable. And there’s a good reason for that. While experts have theorized that factors such as a lack of sleep and dehydration due to the heat can lead to a general bad mood, a new study has proven that the link between hot weather and bad moods actually exists.

Researchers at Pennsylvania’s Lehigh University decided to test the theory that heat causes antisocial behavior. The three-part study, led by professor Liuba Belkin, looked at three different environments.

A new study confirms that a heatwave will make you less friendly. (Photo: Getty)

The first analyzed secret shopper data from a Russian store, comparing reports from July and August of 2011 — a normal summer — to the same months in 2010, when Moscow was experiencing a mega heatwave.

In the summer of 2010, secret shoppers’ data showed a significant drop in the helpfulness from store employees.

Researchers found that 59 percent of retail employees were less likely to help customers or make suggestions and listen actively.

Belkin believes the heat was the reason for the change in attitude. “To our knowledge, this was the first study to establish the connection between ambient temperature and a reduction of prosocial behavior with data,” she told Quartz.

However, other experiments have proven to bring similar outcomes. One Minnesota-based study even showed that we’re more likely to tip more generously on cooler days.

Staying cool and hydrated can help your summer mood. (Photo: Getty)

Belkin went further, embarking upon two more studies that examined the relationship between heat and how people felt. As research, she recruited 160 subjects in the U.S., asking half of them to close their eyes and think of a time when they felt extremely hot. Participants were then asked to answer survey questions about their mood and energy levels followed by a round of trivia questions. Finally, they were asked to fill in an extra survey as a final courtesy.

A control group did the exact same thing. However, they weren’t asked to recall a warm environment.

The results showed that 44 percent of the first group agreed to the optional survey compared to a much higher 77 percent in the control group. The first group also reported suffering from fatigue and lower moods more than the second.

Belkin concluded that simply thinking about a hot environment can lead to tiredness and a bad mood.

Her final study involved a group of students. Some were made to listen to a lecture in a room with a temperature of 80 degrees. Another class did the same but in a fully air-conditioned room. Both classes were asked to answer some questions and then fill out a 100-question survey.

The people in the hot room answered an average of six questions, whereas the students in the cooler location answered an average of 35.

“The point of our study is that ambient temperature affects individual states that shape emotional and behavioral reactions,” Belkin added.  “So people help less in an uncomfortable environment, whatever the reason they come up with to justify why they cannot do something.”

Bottom line: If your office is complaining about a less-than-productive workforce, try hinting at a better A/C system.

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