You went to bed at a decent time and got eight hours of sleep. So why do you still feel exhausted even though you are getting enough sleep?

New research suggests that sleep quality may matter as much as sleep duration, with your bedroom environment potentially playing a role in your sleep quality.

Your bedroom could be affecting your sleep quality

Researchers at Penn State analysed data from 372 young adults, average age 22, who tracked their sleep for 14 days. They published the results in Sleep Health.

Participants reported whether light, noise or temperature disrupted their sleep. They also wore wrist sensors to objectively measure aspects of their sleep.

The findings suggest that bedrooms perceived as too bright, too hot or too noisy were associated with poorer sleep quality, even though these disturbances did not appear to reduce the total amount of sleep participants got.

Too bright, too hot or too noisy?

Each environmental factor affected sleep differently. When participants considered their bedrooms too bright, they tended to fall asleep later, experience poorer sleep quality and spend more time awake during the night.

Excessive heat and noise were also associated with poorer sleep quality, according to the researchers.

Noise can be particularly disruptive because parts of the brain remain alert to the surroundings during sleep, explained study co-author Orfeu Buxton, a professor of biobehavioral health at Penn State. Interestingly, a bedroom being too cold had no measurable effect in the objective sleep data.

The researchers also noted that what feels too noisy or uncomfortable for one person might not bother someone else. Rather than measuring specific noise levels, temperatures or brightness, they focused on how participants perceived their sleeping environments.

Why eight hours might not be enough

Sleep quality involves more than the number of hours spent in bed. How quickly you fall asleep, how often you wake up and how long you remain awake during the night all matter.

The researchers suggested that young adults might compensate for disrupted nights by sleeping in, potentially explaining why their sleep quality suffered without a reduction in total sleep duration. However, further research is needed.

Healthy sleep habits matter at other stages of life, too. Research has also explored the relationship between teenagers’ sleep patterns and mental health, including a weekend sleep habit linked to depression risk in teenagers.

Could simple changes help improve your sleep quality

The researchers suggest that small adjustments could help people who cannot fully control their sleeping environments.

Earplugs or noise-cancelling devices may help reduce unwanted noise, while sleep masks or blackout curtains can block excess light. Keeping your room comfortable during hot weather may also be worth prioritising.

The study focused on young adults and identified associations rather than proving that environmental changes directly improve sleep. Nevertheless, it highlights that getting enough hours in bed does not necessarily mean getting good-quality sleep.