1. Plenty of R&R (rest and relaxation) can boost your mood, focus and energy. Conversely, people with poor sleep habits experience higher levels of stress, depression and anxiety.

2. Want your kids to get A’s and B’s? Make sure they catch their Z’s. Well-rested equals alert in the classroom, and a regular sleep routine may boost math and literacy scores. Some schools are even starting later in an effort to help kids improve learning.

3. Reap the benefits of beauty sleep. When the body is sleep-deprived it produces more of the stress hormone cortisol. Cortisol can cause weight gain and oily skin.

4. Getting your eight hours in could cut your risk for chest pain, heart attack and stroke. A recent study by West Virginia University indicates that people who sleep five hours daily are more than twice as likely to experience these problems.

5. Rest is a responsibility, and apparently so is justice. In a study that appears in SLEEP, Swedish naval officers were more likely to act morally and make moral judgments when fully rested.

1. Your thyroid helps regulate your sleep patterns. An overactive thyroid (hyperthyroidism) can cause difficulty sleeping, fatigue and irritability.

2. Believe it or not, menstruation can affect your sleep patterns. Two in three women experience menstrual insomnia—disturbed sleep due to tossing and turning and general menstrual discomfort.

3. Maybe you do sleep, but continue to experience tiredness regardless of how much sleep you get? If you snore, have a dry throat on waking or regularly become irritable, you may want to talk to your doctor. This could be a symptom of sleep apnea.

4. Your sweetie slumbers soundly while you lay awake at night, so you decide to wake him up. Sound familiar? Ladies, you may have a case of sleep envy. You’re not alone, either. Up to 40 percent of women envy the ease with which their darlings doze. Jealous much?

5. Some people toss and turn through the night before finding sleep. If this is caused by painful or irritating tingling or tugging in your lower limbs, you may have a condition known as restless leg syndrome (RLS).

Want to keep up with the latest sleep science? Visit the National Sleep Foundation site or check out the journal SLEEP.

Puberty normally starts between ages 9 and 16; girls may not notice any physical changes until 11 to 16 years of age. Today, however, some girls are starting to see changes as early as age 6 or 7.

A research team backed by the Breast Cancer and the Environment Research Centers (BCERC) originally set out to more clearly categorize girls into pubertal maturity stages. What they found was that among roughly 1,200 girls aged 6-8, many showed early breast and pubic hair development.

Ten percent of white girls at age 7 had “breast development to some extreme”, as did 23 percent of black and 15 percent of Hispanic girls. These numbers jumped to 18, 43 and 31 percent for 8-year-old participants. Authors agreed that these rates were much higher than 10 and 30 years ago.

Possible explanations include increased exposure to hormones, such as estrogen. Another hypothesis is that environmental pollutants such as BPAs and parabens may be pushing young girls into puberty. Genetic mutations, endocrine disorders and other health concerns are also on the list, but researcher Dr. Abby Hollander of Washington University’s School of Medicine says we can expect to wait for any real answers.

Hollander and colleagues plan to further investigate ways the environment may affect the onset of puberty. Until then, read more from ABC News or see the study’s abstract in Pediatrics.