It's easy not to think twice about your bowel habits until suddenly things don't flow as usual. The best way to ease constipation is to identify its root cause. While increasing fiber and water intake can help, some underlying causes may not be resolved by these measures. Constipation is extremely common, affecting nearly everyone at some point. However, the risk of chronic constipation, defined as symptoms lasting three months or more, increases with age. If you're suddenly grappling with constipation and a lack of fiber and water isn't the culprit, consider these surprising causes.
Sleep Deprivation
Research suggests that insomnia, poor sleep quality, and insufficient sleep duration all raise your risk of constipation. Sleep deprivation disrupts normal colonic function because your colon operates on a 24-hour circadian rhythm, regulating gut movement. Your gut is more active in the morning and slows down at night; lack of sleep can throw this cycle off, raising the odds of constipation. Additionally, inadequate sleep impacts the gut-brain axis and increases stress hormones like cortisol, which are linked to constipation.
Antihistamines
Allergy treatments may affect gut health. Antihistamines have anticholinergic effects that suppress the parasympathetic nervous system, reducing involuntary muscle movements and functions like digestion. This can reduce gut motility, or how fast things move through your gut. However, newer antihistamines such as loratadine, cetirizine, and fexofenadine are less constipating.
Calcium Supplements
While calcium supplements support bone health, they may slow gut motility. Calcium carbonate decreases smooth muscle contractions in the gut wall, binds to fatty acids and bile acids, and reduces lubrication. They also decrease fluid secretion in the gut, leading to harder stool.
Ignoring the Urge to Go
Constantly ignoring your body's urge to use the bathroom can lead to constipation. Repeatedly ignoring the urge contributes to maladaptive learning and altered rectal sensation. When stool sits in the colon for long periods, water is reabsorbed, making stool dry and hard.
Iron Supplements
Iron supplements can irritate the gut mucosa and slow colonic motility. Oral iron supplements create hard, bulky, dry stool, which is constipating.
Anxiety or Depression
Anxiety and depression can impact the gastrointestinal tract through the gut-brain axis. The prevalence of constipation is nearly twice as high in people with a history of depression and anxiety. Factors include activation of the fight-or-flight response, side effects from medications, and reduced physical activity.
How to Get Relief
Start by ensuring adequate fiber (25–34 grams daily for adults) and water intake (pale yellow urine indicates hydration). Adding kiwis to your diet can improve constipation. Aim for at least seven hours of sleep per night and 150 minutes of moderate-intensity exercise weekly. Check medication side effects for constipation. If needed, try osmotic laxatives like polyethylene glycol or milk of magnesia. For persistent stool consistency issues, add stimulant laxatives like bisacodyl or glycerin suppositories. If constipation is chronic or accompanied by alarm signs such as rectal bleeding or unexplained weight loss, consult a gastroenterologist immediately.
