Sleep is important to your physical, emotional, and mental health. How much sleep you actually need varies from person to person and over time. Most people need about seven to eight hours of sleep a night to feel well rested.

In general, the best way to tell if you're getting the sleep you need is to notice how you feel throughout the day. If you feel alert and you function well, you're probably getting enough sleep.

Of course, many people have times when it's hard to fall asleep or stay asleep. It's common to:

• Wake up briefly once or twice during the night and fall back to sleep
• Sleep poorly for two or three nights in a row, especially during stressful times
• Tend to get less sleep as you age

Most people still manage well the day after a rough night of sleep and make up for lost sleep the next night. However, worrying about lost sleep can create stress, and that stress can contribute to ongoing problems falling and staying asleep (insomnia). Many other factors also can play a role in poor sleep.

On a daily basis, poor sleep can affect your:

• Energy level
• Emotions
• Memory and learning
• Ability to think clearly and make decisions
• Ability to focus
• Reaction time
• Desire to be social

Over time, frequent or consistently poor sleep can cause problems with your health, mood, relationships, and performance at work and school.

A number of health concerns may increase your risk of poor sleep, including:

• General health concerns such as hormone changes, allergies and pain
• Mental health conditions such as depression and anxiety
• Sleep disorders such as obstructive sleep apnea, restless legs syndrome and narcolepsy
• Side effects of certain medications

If you're like most people with insomnia, however, your habits and routines play the biggest role in keeping you awake at night. Common, nonmedical causes of sleep disruption include:

• Drinking too much caffeine
• Keeping an irregular bedtime schedule
• Working too late in the evening
• Napping during the day
• Eating too much before bedtime
• Drinking alcohol before bed
• Sleeping in an uncomfortable environment
• Using your bed for work, eating or watching TV
• Engaging in stimulating activities before bed
• Using computers, video games, smartphones or other electronic devices just before bed

In many ways, insomnia is a side effect of the times we live in. It's common to multitask, watching TV at the same time you work on a project. You may make phone calls, answer emails and text messages, pay bills, and work on projects right up until bedtime. This keeps your brain stimulated, making it hard to settle down and fall — or stay — asleep.

There are many changes you can make to start sleeping better. Start building these proven habits:

• Stick to a regular sleep schedule. Keep your bedtime and wake time consistent from day to day, including on weekends.
• Minimize stimulation before bedtime. This includes turning off devices and screens. Allow time for a soothing wind-down routine.
• Make your bedroom an inviting place to sleep. Keep it dark, cool and quiet.
• Learn skills to relax more and stress less. Proven techniques that help with sleep include mindfulness practices such as meditation and guided imagery.

With these changes, you're likely to start sleeping better within a few weeks.