Teen Dreams: Sleep and the Adolescent Brain

The teen years are a period of major brain transformation as pathways rewire and mature in response to hormone shifts, biological changes, and interactions with society. A lot is going on under the surface, and our understanding continues to evolve rapidly with advances in magnetic resonance imaging (MRI) and other technologies that offer a glimpse into the developing mind. Adolescent brain development is a mix of expansion and regression as the brain overproduces specialized neurons while pruning back unused, outdated connections. The process is similar to fruit trees sending out lots of branches in the spring, which a gardener then prunes back to maintain a healthy tree. Synaptic pruning is a hallmark of adolescent development and is thought to weed out neurons and synapses that fail to make relevant connections. It is highly specific and variable: in some brain regions little is changed, while in others up to half of all connections are pruned back!

Interestingly, the growth and pruning temporarily limits the influence of the prefrontal cortex (PFC), the brain region responsible for planning and impulse control, and which research reveals tends to mature last, partially explaining why teens engage in high-risk behaviour. Further, the amygdala, the part of the brain that responds to threats, activates much less in teens when presented with adverse stimuli and outcomes than in adults. As well, certain brain regions become more sensitive to dopamine-reward circuits, the brain neurotransmitter responsible for pleasure and motivation, peaking in mid-adolescence and then declining into adulthood. Dopamine sensitivity to sweets, for example, is much higher during ages 11–15 than during early adulthood (19–25 years). With all this going on, supporting healthy development during adolescence is vital. A balanced lifestyle goes a long way, and should include healthful nutrition, stress management, exercise, and sound sleep, with emerging research pointing particularly to sleep as a key factor for healthy brain growth. 

THE BEDTIME BRAIN

The brain pathways that favour higher-risk behaviour in teens is known as “hot cognition,” and sleep deprivation tends to reinforce these circuits. During adolescence, there is a biological shift towards delayed sleep onset and later waking, which commonly leads to deprivation during the school week. Given the link between sleep deprivation and hot cognition, shifting to later school start times makes a lot of sense. Along with later waking, teens require more time spent sleeping than adults. Nine to eleven hours of uninterrupted sleep is vital.

Available research reveals the complex ways that sound sleep supports healthy development. Each sleep stage provides unique benefits to the adolescent brain. During stages one and two, the brain produces alpha and theta waves as well as sleep “spindles,” which are upswings of wave frequency. Sleep spindles increase following daytime learning of motor tasks, and help teens “practice” an activity during sleep, solidifying the coordination and steps. Transitioning into stages three and four, longer delta waves form in response to the calming neurotransmitter GABA, encouraging deep sleep. During this phase, growth hormones pulse throughout the body, promoting growth and repair of muscle and body tissue. Delta wave sleep also improves immune function and helps prevent illness. Researchers observed lower white blood cell counts with even mild decreases in delta wave sleep. Regular deep sleep also promotes lean muscle mass and weight loss by regulating metabolism.

The next phase of sleep is Rapid Eye Movement (REM), the time of night where dreaming occurs. REM is a unique phase to mammals and birds and is an essential resting and refueling period. Rhythmic generations of REM are triggered by neuronal activity from the brain stem, and during REM the brain stem takes over central control and regulates body function. By handing over control, the brain resets other neurotransmitters—particularly serotonin, dopamine, and norepinephrine. The neuronal activity during REM also causes dreaming, which is based on signaling from the brain stem to other brain regions, forming waves of activity that encourage the body to continue sleeping and send complex data about motor control and perception to the nervous system. In the deeper REM phase of sleep, the brain perceives the stimuli from the waves as real, activating sensory perception, which gives dreams their vivid, three-dimensional quality. As the waves reach the hippocampus, long-term memory storage is promoted and memories are reorganized and streamlined, improving creative function and learning. Sleep waves are particularly important for teen development, as this is the main time for the pruning and growth described above.

NATURAL SLEEP SUPPORT

By supporting memory, learning, immune system health, neurotransmitter balance, and overall growth and repair, sleep is clearly vital to adolescent wellbeing. The teen years bring a host of new demands on time, like sports and extracurricular and social activities. Along with increased use of caffeine products and late night TV and computer use, sleep problems are quite common in adolescence. Lifestyle steps and natural therapies provide effective support, so your teen can reap all the benefits of sleep during this critical time.

Preparing the Nest

Environmental approaches are a natural starting place for sleep support. For teens, technology has a significant impact on sleep quality. Electromagnetic frequencies (EMFs) from WiFi and cell phones impact circadian rhythm by increasing stress hormones like cortisol. Blue light from computer and smartphone use also causes sleep disturbance. A recent review at Harvard University found blue light suppresses melatonin, leading to difficulty falling asleep and prolonged cortisol secretion. Switching off routers and phones in the evening and investing in blue light filtering screen covers and glasses can help reduce exposure.

Hit-the-Sack Herbals

Botanicals have a centuries-old history of supporting healthful sleep. In particular, relaxing herbs, called nervines, lower stress hormones while promoting calming neurotransmitters for deep, sustained sleep.

Each of the following herbs can be taken as a tea (1–2 cups) or as a tincture/glycerite in a little water 30 minutes before bed. For chamomile tincture, increase to two droppersful, and for lavender, reduce to ½ dropperful.

Nervine herbs for sleep support

Ashwagandha Chai

A gentle, caffeine-free, warming tea that supports relaxation and sound sleep.

Ingredients

• 1 c almond milk
• 2 tsp ashwagandha powder
• 1 tsp honey
• 4 slices fresh ginger
• ¼ tsp each cardamom, cinnamon, nutmeg, clove
• 1 each rooibos and tulsi tea bags

Instructions

1. In a small saucepan, bring all ingredients except tea to a simmer.
2. Remove from heat, add tea bags and let steep for 10 minutes.
3. Drink while warm.

Sweet Dreams Cuisine

Eating a variety of vegetables, fruits, healthy fats, and proteins replenishes neurotransmitters and hormones involved in the sleep cycle. In particular, vitamin B6, magnesium, tryptophan, L-theanine, and omega-3 fatty acids support healthy sleep and overall mood. Vitamin B6 encourages serotonin conversion to melatonin, and is found in pistachios, pumpkin seeds, almonds, poultry, cold water fish, leafy greens, potatoes, and bananas. Magnesium promotes a healthy nervous system as well, and is found in nuts and seeds, dark leafy greens, fish, and whole grains. Along with boosting these nutrients in the diet, supplementing with vitamin B6 and magnesium is effective for healing insomnia.

Certain amino acids also regulate our sleep-wake cycle. Tryptophan, found in poultry, oats, dates, dairy, and seeds, encourages melatonin, helping with sleep onset. (To increase absorption, combine tryptophan with a whole grain, like sliced turkey on whole grain bread.) Found in green tea, the amino acid L-theanine increases GABA synthesis, while glycine, readily available in high protein foods like fish, eggs, legumes, dairy, and meat, promotes sleep onset and deep stage sleep. In research, supplemental glycine improves both sleep onset and sleep quality for people with insomnia.

Maintaining optimal vitamin D is more difficult and plays an important role in northern climates. With vitamin D deficiency, the body releases inflammatory compounds called cytokines, which interfere with serotonin conversion to melatonin. Increasing vitamin D levels, especially in the winter, is a key step for circadian rhythm health. Additionally, avoiding caffeine and chemical additives, and focusing on an anti-inflammatory diet creates a solid foundation for sleep health.

We already know for certain that healthy sleep is a core foundation for adolescent wellness, and for most teens lifestyle steps alone can foster optimal sleep patterns. Research continues to unravel the mysteries of the developing brain, and with continued advances in sleep science our understanding will continue to grow. If more help is needed, try these natural therapies for a safe, effective boost.

You may also enjoy: Bedtime Sleep Techniques for Restless Kids, How Much Sleep Do Kids Need?, and Sleep Science: Why Sleeping is Important.