Dr. Lindsay Dewa on Steps to a Healthier Nighttime Routine

With a PhD heavily focused on insomnia and now working for Imperial College London’s Faculty of Medicine, Dr. Lindsay Dewa explores the necessary steps for achieving a healthier nighttime routine.

Is there a science to the number of hours we should be getting nightly?

Everyone is different. Some people need more sleep than others, and this changes with age:

• Babies: Around 14-17 hours.

• Older Adults: Usually 5-7 hours.

Thatcher’s apparent 4 hours of sleep? That’s not the norm. Most people need at least 8 hours to feel refreshed. The key is how you feel—if you can concentrate, socialize, and generally feel okay, you don’t have insomnia, even if you only get 4-5 hours per night.

Is there a sweet spot for bedtime to maximize sleep quality?

There’s no universal bedtime—it varies by individual. Some people are night owls, staying up and waking later, while others are early risers or larks.

The critical factor is consistency: go to bed and wake up at the same time every day. This routine promotes good sleep hygiene.

What about naps? Helpful or harmful?

Napping can have mixed effects depending on the individual:

• In Mediterranean cultures, siestas are normal and don’t negatively affect nighttime sleep.

• In the UK, daytime naps can make nighttime sleep more challenging by reducing sleep pressure.

A 10-minute power nap between 1-3 pm can help reboot energy levels. Avoid naps longer than 20 minutes to prevent grogginess. Remember, naps are not a replacement for quality nighttime sleep.

How does lack of good nighttime sleep impact mental health?

Poor sleep can significantly impact mental health:

• A single bad night may result in feeling down, low energy, and reduced motivation.

• Chronic poor sleep (e.g., insomnia) can lead to severe and lasting psychological issues.

Interestingly, addressing sleep problems (e.g., through cognitive behavioral therapy for insomnia, CBTi) can improve both sleep and mental health outcomes.

What qualifies as insomnia?

Many people think they have insomnia after a few bad nights of sleep, but true insomnia meets the following criteria (DSM-V):

1. Sleep problems persist for at least three months.

2. Difficulty occurs at least three nights per week.

3. Problems initiating or maintaining sleep, or waking early and unable to return to sleep.

4. Daytime impairments (e.g., poor functioning, cognition, or behavior).

5. Sleep difficulties occur despite the opportunity to sleep.

Around 10-15% of people worldwide experience insomnia, while about a third report general sleep problems.

Should more people seek professional help for sleep issues?

Not everyone needs medical treatment for occasional bad nights. Instead, focus on better sleep hygiene:

• Go to bed and wake up at the same time daily.

• Keep your bedroom cool, dark, and only for sleep or sex.

• Avoid stimulants like caffeine after 3 pm.

For persistent sleep problems, consulting a GP can help. Cognitive Behavioral Therapy for Insomnia (CBTi) is the gold standard for long-term sleep issues, combining techniques like:

1. Sleep hygiene

2. Stimulus control

3. Relaxation therapy

4. Cognitive therapy

5. Sleep restriction

Online CBTi options, like Sleepio, offer accessible alternatives, with NHS patients in London eligible for free access.

How do smartphones and screens impact sleep?

Using phones or laptops before bed disrupts circadian rhythms due to blue light exposure. Sleep scientists recommend:

• A wind-down routine: Avoid screens at least two hours before bedtime.

• Go to bed when you feel sleepy—don’t fall asleep on the couch first.

Is it okay to listen to music or podcasts to fall asleep?

Yes, if it’s already part of your routine. For some, music or TV is a calming wind-down ritual. For others, introducing this could disrupt sleep.

Can sharing a bed affect sleep quality?

It depends. A partner’s snoring or restlessness can negatively impact sleep, but many couples adjust to each other’s patterns. For some, sleeping apart temporarily (e.g., when a partner returns from a trip) might cause disruption until re-adjusted.

Do you agree with neuroscientist Matthew Walker’s idea of prescribing sleep?

In part, yes. Sleep is often undervalued compared to mental health issues like depression or anxiety. However, the growing focus on sleep research, education, and public awareness—thanks to books and studies like Walker’s—is helping highlight its importance.

What insights have emerged from your research?

My research has focused on sleep in secure environments, such as prisons in England. Findings include:

• Nearly two-thirds of prisoners meet the DSM-V criteria for insomnia.

• Causes overlap with the general population (e.g., depression, anxiety, physical health issues) but are compounded by the prison environment.

• NICE guidelines for insomnia treatment are often not followed in prisons, even though care should be equivalent to community standards.

Our recent findings suggest psychological treatment paired with peer support could be effective in prisons. Stay tuned for our published results!