Catching Colds in the Summer Heat

Common cold in summer months caused by enteroviruses

/ Author:  / Reviewed by: Robert Carlson, M.D

The sun is out, the air is warm, people are putting on their swimsuits and heading to the pool, and you are…blowing your nose and shivering under the covers?

A summertime cold can seem like an especially cruel twist of fate. Where do these fair weather flus come from? And are there any steps that can help prevent their arrival?

A Different Animal

According to the National Institutes of Health (NIH), over 200 different viruses can lead to the uncomfortable common cold symptoms like a running nose and an itchy throat.

“The colds we catch in winter are usually triggered by the most common viral infections in humans, a group of germs called rhinoviruses,” NIH reported.

These rhinoviruses survive better in colder weather and, according to NIH, “Their numbers surge in September and begin to dwindle in May.”

When attacked by a cold during the warm months, there is likely a different germ to blame. According to NIH, the culprit is likely something called a non-polio enterovirus infection.

Though the name may not be familiar, these germs are the second most common type of virus (second only to the winter cold-causing rhinovirus) to affect humans.

NIH estimated that “nationwide, enteroviruses cause an estimated 10 million to 15 million illnesses each year, usually between June and October.” And their effects can go beyond just the sniffles. 

In an interview with dailyRx News, Jocelyn Ang, MD, of the Division of Infectious Diseases at the DMC Children’s Hospital of Michigan, explained, "The genus enterovirus contains different types of viruses that produce a broad range of illnesses and result in variable clinical manifestations."

According to Dr. Ang, enteroviruses may cause sores in the mouth, skin rashes, vomiting, diarrhea, eye infections and infections and inflammation of muscles, or they may cause more minor symptoms often associated with the common cold, like nasal congestion and nasal discharge.

These viruses can be more serious than wintertime colds, and not just because they strike when everyone else is playing in the sunshine.

In an interview with NBC News, Bruce Hirsch, MD, infectious disease physician in New York said, "Winter cold viruses tend to make you feel really sick, and then you get over it. Summer colds just seem to lurk in the background...and just go on and on and on."

Exposure Risks

We often know when we are exposed to cold viruses in the wintertime – what with everyone sneezing and sniffling – but how do we know when we are exposed during the summer?

The presence of these enteroviruses makes a strong case for washing your hands often, even when it’s not necessarily “flu season.”

The viruses can live for hours on surfaces and items. “We cannot avoid touching contaminated surfaces in public transport and crowded areas, but it is good sense to wash our hands when we sit down to eat or relax,” suggests the Common Cold Centre of Cardiff University in the United Kingdom.

Just like heaters can contribute to respiratory symptoms in the winter, air conditioners can contribute in the summer. Being constantly exposed to re-circulated air “can dry out the lining of the nostrils, giving an open port to viruses,” NBC News reported.

As hoards of people prepare for summer travel, airplanes can be a source of exposure to summertime cold viruses, both because of the circulated air and the large numbers of people contained in a small space.

“Long haul jet flights appear to pose a special risk as there are no other periods when we are likely to be squeezed as tightly together with 400 potential sources of common cold infection,” explained Cardiff University. “The chances are that several of our fellow passengers will have a cold and the confined space of a jumbo jet is an ideal environment for transmission of airborne disease.”

Preventing a Cold in Heat

In order to protect against a summertime cold, there are steps that can be taken. As mentioned earlier, no matter what time of year, care should be taken to wash hands before eating or touching your face.

According to Dr. Ang, enteroviruses usually are transmitted through the gastrointestional tract.

"Infection is transmitted by ingestion of virus from infected persons that is shed in the stool or upper respiratory tract secretions," explained Dr. Ang.

For this reason, Dr. Ang recommended taking special care when washing hands after dealing with soiled diapers, and making sure to disinfect any contaminated surfaces. 

It is also wise to take extra precaution when exposed to more people and potentially more enteroviruses. For example, you might carry hand sanitizer with you during plane travel and avoid close contact with people who have a cold themselves, NBC News suggested.

NBC News also recommended making sure to stay hydrated, eat a balanced diet and get plenty of sleep to help your immune system stay strong, which is probably sound advice for anytime of the year.

One more interesting piece of advice that might not be so common sense: people shouldn’t jump headfirst into an intense new summertime exercise routine when they’ve been sedentary through the winter months.

Dr. Hirsch told NBC News, “In summertime, we go outdoors and exercise vigorously, maybe when we're not in great shape. That's when these enteroviruses like to show up."

People should take a more moderate approach and ease into new exercises and physical activities gradually, giving the body time to adjust. Your immune system (and probably your muscles, too) will thank you for it.

Reviewed by: 
Review Date: 
May 6, 2013