Email was designed to optimize communication and workflow, but the benefits may come at the cost of employees' well-being.

The study, by researchers Tom Jackson, Gillian Ragsdell, and Laura Marulanda-Carter of Loughborough University, explored the effect email had on employees at a UK government agency. Mental and physical toll were quantified by tracking the blood pressure, heart rate, cortisol levels, and the 30 participants' diaries of their experience throughout their workday.

Eighty-three percent of employees became more stressed while sending and receiving email correspondents. Blood pressure, heart rate, and cortisol levels — a hormone that is secreted by the adrenal gland — all increased in response to email activity. However, the response depended completely on the type of email. Employees showed a positive response to timely information that was helpful to their workload, and responded with gratification once the work was complete via email. The study found that irrelevant emails, emails that required immediate attention, and interruptions from their work all caused negative responses of irritation.

Participants shared reasons why emails caused them stress. Among the top reasons included misinterpretation, increased expectations, and alienation. Even though they identified possible causes of stress, participants could not accurately identify when their bodies were exhibiting signs of stress.

The reasoning could be the tone of the email language. According to a study published last month by the software company, Contactually, negative emails had quicker responses than positive ones. The study also found that unhappy people are more likely to respond to emails within 24 hours compared to their happier colleagues. Contactually's engineers monitored 100 million email conversations by analyzing negative and positive keywords, then calculated based on the expediency of response.

The Loughborough study also found that multitasking email with phone conversations or face-to-face meetings increased stress levels in 92 percent of the study's participants.

According to The Telegraph, lead researcher Jackson said, "The brain can only deal with eight to 12 tasks at any one time and if you can't shut those tasks down you start to become overloaded and fatigued."

Emailing is only one of the many stressful events an employee may experience throughout the day. Although stress is the body's instinctual response to protect against threats such as predators and aggressors, too much stress can pose as a serious health risk, according to Mayo Clinic. Overexposure to stress hormones can lead to heart disease, sleep and digestive problems, depression, obesity, memory impairment, and worsening of skin conditions, such as eczema, according to Mayo Clinic.

Cortisol controls many functions in the body at times of stress within the immune, digestive, and reproductive systems. The cocktail of hormones circulating throughout the body during stress-induced times affect regions in the brain, which control mood, motivation, and fear. Hence, a person's mood alters readily when under stress.

The American Psychological Association (APA) lists several reasons employees become stressed in the work place. Recent downturns in the economy have made the employment uncertainty a source of concern for millions. According to the APA, workplace stress can derive from a sense of powerlessness, dissatisfaction in job description, a job that doesn't match their skillset, and work setting. Chronic stress, in addition to a poor communication medium, such as email, places even more stress burden on the average employee. With many people spending about 25 percent of their adult lives working, one can only conclude that the fewer causes for stress, the better.