If you’ve been using a sleep tracker—i.e. an Apple Watch, Fitbit, Oura Ring, or another device—and have noticed your deep sleep (or slow-wave sleep) stats seem consistently low, you might be wondering if there’s anything you can do to improve those numbers. Good news: there is.
But first, let’s talk about why deep sleep is so valuable for your health and fitness goals, how much you really need, and then we’ll dive into science-backed ways to improve it.
What Is Deep Sleep (Slow-Wave Sleep)?
Deep sleep is the most physically restorative stage of your sleep cycle. It typically occurs in longer stretches during the first half of the night and is characterized by slow brain waves, lower heart rate, and relaxed muscles. While all stages of sleep serve a purpose, deep sleep is where the real “repair work” happens.
Here’s what your body is doing during deep sleep:
- Muscle Recovery & Growth: This is when your body releases the most growth hormone (HGH), which helps repair muscle tissue broken down during training and supports lean muscle development. A 2023 review in Frontiers in Physiology noted that disruptions in deep sleep can impair muscle recovery, potentially slowing progress for athletes and fitness-minded individuals.
- Cognitive Health & Memory: Deep sleep helps consolidate memories, process information, and clear waste from your brain through the glymphatic system. Research published in Science (2023) suggests poor deep sleep may be linked to long-term cognitive decline.
- Immune Support & Metabolism: This stage is also linked to immune system regulation, blood sugar control, and overall metabolic function.
- Mood & Mental Health: Lack of deep sleep has been associated with higher rates of anxiety, depression, and emotional dysregulation. According to a 2022 study in Sleep Medicine Reviews, improving slow-wave sleep may positively influence mood and resilience to stress.
How Much Deep Sleep Should You Aim For?
For most healthy adults, deep sleep typically makes up about 13–23% of total sleep time. If you’re sleeping 7–8 hours per night, that translates to roughly 60 to 110 minutes of deep sleep.
That said, individual needs can vary. If your sleep tracker consistently shows less than 60 minutes of deep sleep—even with sufficient total sleep—it might be worth taking a closer look at your routines, sleep environment, and overall health habits.
Why Are My Deep Sleep Numbers So Low?
First, don’t panic. Sleep trackers aren’t 100% accurate when it comes to precisely measuring sleep stages. However, they do give you useful trends over time.
If you’re consistently logging low deep sleep, common culprits may include:
- Irregular sleep schedule
- Poor sleep environment (light, noise, temperature)
- Late-night eating or caffeine
- Elevated stress or anxiety
- Alcohol consumption
- Lack of daily physical activity
- Underlying sleep disorders (like sleep apnea)
How to Improve Deep Sleep
If you’re ready to boost your slow-wave sleep, here’s a game plan backed by recent research:
1. Keep a Consistent Sleep Schedule
Your brain thrives on routine. Going to bed and waking up at the same time daily—even on weekends—helps regulate your sleep homeostat, building natural pressure for deep sleep. Even a one-hour weekend sleep-in can throw off this rhythm.
2. Optimize Your Sleep Environment
- Keep the bedroom cool (60–67°F). Research shows that a lower core body temperature helps initiate deep sleep.
- Block out all light (blackout curtains or a sleep mask).
- Eliminate noise (earplugs or white noise machines can help).
3. Time Your Workouts Wisely
Exercise promotes deeper sleep—but timing matters. Studies in Journal of Clinical Sleep Medicine (2022) suggest that resistance training or cardio earlier in the day can increase slow-wave sleep, while late-night high-intensity workouts may delay it.
4. Watch What (and When) You Eat & Drink
- Limit caffeine after lunchtime.
- Avoid heavy or high-fat meals 2–3 hours before bed.
- Stay hydrated, but taper fluids to minimize overnight bathroom trips.
- A small protein-carb snack (like turkey on toast) may help promote sleep-inducing tryptophan.
5. Be Smart About Alcohol Timing
While a glass of wine may help you feel drowsy initially, alcohol can interfere with your body’s ability to reach and sustain deep sleep. As alcohol metabolizes—usually a few hours after you fall asleep—it tends to fragment sleep, reduce slow-wave sleep, and cause more awakenings.
Research in Sleep Medicine Reviews (2022) confirms that even moderate evening drinking can shorten deep sleep duration and lower sleep quality. If you choose to drink, aim to stop at least 3–4 hours before bedtime to give your body time to fully process the alcohol.
6. Incorporate Relaxation Techniques
- Practice deep breathing or progressive muscle relaxation before bed.
- Limit screen time 30–60 minutes before sleep; blue light disrupts melatonin production.
- Consider mindfulness or guided meditation, as they are both beneficial for improving slow-wave sleep.
7. Consider Supplementation
several compounds and herbal blends are known for their roles in supporting deep sleep. That said, before adding any new supplement to your diet regimen, please consult your healthcare provider. Here are some considerations:
- Magnesium (200–400mg): May relax muscles and regulate stress hormones.
- Glycine (3g): Shown in small studies to lower core body temperature and increase deep sleep.
- L-theanine (100–200mg): Promotes calm without sedation.
- Herbal blends: Nutrishop's newly launched Nu-Tek Nutrition’s Sleep Formula combines key ingredients GABA, L-theanine, glycine, inositol, lemon balm, passionflower, chamomile, and saffron extract (Affron®), which may help support relaxation, reduce stress, and promote more restful sleep.
8. Use Your Sleep Tracker as a Tool
Sleep trackers shine when you use them to monitor trends—not obsess over nightly numbers. Make one change at a time and watch how your deep sleep minutes shift over 1–2 weeks.
9. Rule Out Underlying Conditions
If your deep sleep remains low despite your best efforts, speak with your doctor. Conditions like sleep apnea, anxiety, or depression can fragment deep sleep. Addressing these issues can often lead to dramatic improvements.
Small Gains Matter
Even increasing your deep sleep from 45 minutes to 60 minutes can make a real difference over time—more energy, better workouts, sharper thinking, and a stronger immune system. But these improvements take consistency. As researchers point out, it often takes 2–4 weeks of consistent changes before deep sleep stabilizes at higher levels.
Bottom Line:
Think of deep sleep like your body’s nightly repair shop. When you prioritize it, everything else—muscle recovery, memory, mood, and even metabolism—tends to work better.
