Fitness is no longer a hobby: these days, keeping in shape is a lifestyle. Turn to social media, and you’ll find reams of images of toned, young things perfecting their squats in the gym.
The number of Americans with gym memberships has risen three-fold, to 62.5million, according to Bloomberg, and roughly a fifth of adults workout every day.
Although health officials say the average American should be doing more exercise, some experts have warned that some are in fact doing too much.
And the consequences could be life-changing.
Alexandra Davidson, a New York-based nurse practitioner with a doctorate in nursing practice, who has worked in family medicine for six years, raised the alarm over the risk of bone fractures, immune system problems and even muscle breakdown for those who over-do it in the gym.
The majority of the risks of over-exercising are related to an excess of the stress hormone cortisol, which interferes with a number of vital hormones
Writing for a medical blog, Ms Davidson raised concern that ‘more is better’ is ‘celebrated within fitness culture when it comes to exercise’. But just how much is too much?
John Gallucci Jr, a physical therapist and CEO of JAG Physical Therapy in New York, told DailyMail.com that the average person should limit intense cardiovascular exercise, like running and aerobics, to five days a week.
And sessions should be no longer than 90 minutes, he said.
Meanwhile, other experts have warned that for some groups, like young women with a body mass index below 19, intense exercise should be even less frequent ‘because they are at greater risk of injury,’ Heather Milton, an exercise physiologist at NYU Langone Health, told DailyMail.com.
Experts have warned against the ‘more is better’ attitude to exercise, which they say could be putting people’s health at risk
Ms Davidson explained that the main risk of excessive exercise is elevated levels of cortisol, the body’s primary stress hormone.
Cortisol – produced by the adrenal glands on top of the kidneys – regulates the body’s stress response, controls metabolism, suppresses inflammation, and influences blood sugar by releasing the sugar glucose into the blood.
The body produces cortisol during stress, such as exercise, along with adrenaline. Both of these keep the body in a fight-or-flight state.
Too much cortisol can interfere with the release of other vital hormones involved with metabolism, hair and nail growth, bone repair and blood pressure – leading these functions to become compromised.
Ms Davidson also said this can result in irregular menstrual cycles due to interference with female sex hormones like estrogen.
Over-exercising also triggers inflammation in the body. While this is the body’s natural response to injuries, excess inflammation can impair vital functions – such as the immune system’s ability to fight intruders and fix damage.
This can result in slower healing from injuries, like muscle strains. Contrary to popular belief, over-exercising doesn’t build more muscle; it diminishes it.
In order for the fibres in muscles to grow, they need adequate rest time – which can be cut short if they are under strain for the majority of the week. Increased risk of aches and pains, which could affect all-important sleep. ‘Rest is important to allow our body time to repair and our muscles to grow,’ said Ms Davidson.
And though exercise has been shown to strengthen bones, Ms Davidson said that exercising too often can increase the risk of stress fracture in certain populations.
One study from the Ohio State University Wexner Medical Center, for example, found that female athletes with a BMI below 19 were five times more likely to sustain a sports injury than their male counterparts. A BMI of 18.5 or lower is considered underweight.
Ms Milton said that women who are underweight tend to have weaker bones than women with a higher BMI. This could make these women more vulnerable to injury from repeated high-impact activity, such as high-intensity interval training (HIIT).
Ms Milton said that while 90 minutes of low-impact exercise, such as cycling or yoga, five days per week is likely suitable for this population, it is advisable to reduce time doing high-intensity exercise to less than five days a week.
The American Academy of Family Physicians (AAFP) suggests underweight women refrain from all high-intensity aerobic exercise because it may cause them to burn too many calories, making it difficult to reach a healthy weight.
And ‘pushing through’ a particularly painful workout could be hazardous too.
‘If you’re in pain, you shouldn’t be doing that activity,’ said Mr Gallucci. ‘If that pain is between the three or four, you should not do that repetitious activity,’ he said.
He said if the pain starts to go to 4-5, speak with a physical therapist or athletic trainer about cutting back and setting appropriate limits.
Ms Davidson suggests varying your routine to avoid overuse injuries. This can include doing a short run and then switching to a yoga routine after, for example, to work different muscle groups.
Source: | This article originally belongs to Dailymail.co.uk