Circadian Rhythm, Sleep, and Stress: What You Need to Know
Your body has a natural clock called the circadian rhythm. It tells you when to feel sleepy, when to wake up, and when to eat.
This clock is controlled by a tiny part of your brain called the suprachiasmatic nucleus (SCN), and it works best when you get sunlight in the morning and darkness at night. 🌞🌙
When you sleep well, your body stays balanced. Sleep helps your brain and hormones work properly.
But if you don’t sleep enough, your body activates a stress system called the hypothalamic-pituitary-adrenal (HPA) axis. Here’s how it works:
– Your hypothalamus releases corticotropin-releasing hormone (CRH).
– CRH signals the pituitary gland to secrete adrenocorticotropic hormone (ACTH).
– ACTH then stimulates the adrenal glands to produce cortisol, the primary stress hormone.
Cortisol helps you stay alert and respond to challenges, but too much of it from poor sleep or chronic stress can mess with your health and make sleeping even harder. So, stress and sleep problems feed off each other — one makes the other worse. 😩🔄
Things like bright lights at night, phone or TV screens, night shifts, and taking care of kids or elders can confuse your body clock.
That’s because your brain thinks it’s still daytime when it’s actually night. This stops your body from making melatonin, the hormone that helps you sleep. 💡📱
Here’s how to fix your rhythm and feel better:
– Morning: Get sunlight early, wake up at the same time every day. 🌅
– Daytime: Move your body, drink water, and avoid caffeine after 2 PM. 🚶♂️💧☕
– Evening: Use warm, dim lights. Turn off screens at least 1 hour before bed. 🕯️📴
– Night: Sleep in a dark, cool room. Try to go to bed at the same time every night. 🌌🛏️
If you have kids, use soft yellow lights in the evening and keep screens away before bedtime. This helps their bodies make melatonin and sleep better. 👶💛
In short, Sleep, light, and stress all affect your body clock. Fix your routine, control your light exposure, and manage stress — your body will thank you.
Tips for Shift Workers, Caregivers, New Moms, and Night-Time Professionals
Shift Workers (Nurses, Police, IT, Etc.):
– Use blackout curtains to simulate night during daytime sleep.
– Wear blue-light blocking glasses after your shift.
– Try to nap before your shift to reduce sleep debt.
– Keep a consistent sleep schedule, even on days off.
Caregivers (Kids or Elders):
– Sync your rest time with theirs when possible.
– Use white noise or soft music to help both of you relax.
– Take micro-breaks for breathing or stretching to lower cortisol.
Post-Pregnancy Moms:
– Sleep when the baby sleeps — even short naps help.
– Accept help from family for night feeds or chores.
– Keep lights low at night and expose yourself to daylight in the morning.
IT Professionals & Night-Time Workers:
– Use screen filters or “night mode” after 7 PM.
– Set a “wind-down alarm” to remind you to stop work and prep for sleep.
– Avoid heavy meals and caffeine late at night.
Dr. Kavitha Sundaravadanam
Senior Family Physician,
Kauvery Hospital, Chennai
