Sleep Stages and Cycles

Taking 4 two hour naps isn't the same as taking an eight hour sleep. Why? Because of the body's sleep cycle as it bounces between Non-Rapid Eye Movement (NREM) and Rapid Eye Movement (REM) sleep.

NREM is essentially dreamless sleep. During which the blood pressure is low, sleep breathing and heart rate are slow and regular. There are different stages of NREM sleep depicting the different depths. (medicinenet.com)

REM is when dreams usually occur. During which the heartbeat and blood pressure is more irregular. It is also usually accompanied  by involuntary muscle jerks.  (medicinenet.com)

When you first fall asleep you first enter NREM1 (~1-7mins), then NREM2 (10-25mins), and NREM3 (20-40mins) where sleep inertia is the strongest. After reaching deep sleep you will ascend back to NREM2 (~5-10mins) then finally into REM sleep. Your sleep will cycle back and forth like this.

Seen below is a pie chart on the average total time spent in each stage of the sleep cycle. However it isn't as simple as dividing the time spent in each stage between the cycles as each cycle will have different proportions of REM and NREM sleep depending on the state of the person.

http://www.howsleepworks.com/types_cycles.html

As you can see, NREM2 takes up a surprisingly large amount of the total time spent sleeping despite the relative benefit it produces. This is because it is the transition phase between deep sleep and REM.

Different stages of the cycle serve different restorative purposes, so the amount of time spent in each stage during each consecutive cycle differs as the night progresses.

Stages	When	What	Benefits
REM	After the ascension from NREM3	* Brain is active and dreams occur * Eyes dart back and forth * Body becomes immobile and relaxed, as muscles are turned off	* Provides energy to brain and body * Supports daytime performance
NREM 1	Occurs first	Light sleep	Nothing
NREM 2	Between phase of NREM 1 and 3	* Becoming disengaged from surroundings * Breathing and heart rate are regular * Body temperature drops (so sleeping in a cool room is helpful	Nothing
NREM 3 & 4	The bottom of the sleep phase	* Deepest and Most restorative stage of sleep * Blood pressure drops * Breathing becomes slower * Muscles are relaxed * Blood supply to muscles increases	* Tissue growth and repair occurs * Energy is restored * Hormones are released, such as: Growth hormone, essential for growth and development, including muscle development

http://sleepfoundation.org/how-sleep-works/what-happens-when-you-sleep

As you can see in the graph below, the amount of time spent in NREM3 stage decreases and time spent in REM increases as the night progresses. Probably explaining why it is much easier to wake up after a long sleep than a short one as you are statistically more likely to catch yourself in the light sleep stages.

http://www.quantadynamics.com/research/performancerem.htm

So to maximize the benefits of time spent sleeping it is better to sleep for an extended period of time than to take multiple naps throughout the day. That being said, beware of oversleeping!

Switching to Minimalist Shoes

Recently there has been a trend of shoes with less cushioning. It originated from the introduction of the book Born to Run, a story about a fascinating running adventure between American cultured runners and members of an isolated tribe called the Tarahumaras who live in the Copper Canyons of Mexico. The book says that these amazing people are able to run 200 miles at a time. These led to the development of the now famous Vibrams that I can't help but stare at because of how weird it looks. After talking Dave Reed, a friend and an MAT specialist, and doing my own research I decided to make the switch and it is advisable for you too. This is why.

Reasons

Under Usage of Muscles in the Foot

The normal cushioned shoes with stability and motion control overprotect your feet. The bulky shoes puts a barrier around your foot muscles and prevents it from doing its job, to react and adapt to the environment. The foot is desensitized to its role and the muscles that help facilitate good running form is handicapped.
This can contribute to injuries in the long run. In particular plantar fasciitis which affects approximately 10% of Americans. The plantar fascia is the muscle under that supports the arch of the foot. It aids in the pronation of the foot that helps absorb the impact of when the foot strikes the ground. With it being handicapped, it is not able to buffer the impact of the foot strike and over a long period of time or long runs the effect becomes more apparent.

Increased Impact on Legs and Body

Cushioned shoes generally have very high heels which encourage a heel strike running style as the cushioning not only makes it more comfortable to do so, the shape of the wedge alters the runner's gait.

Foot strike without shoes

Foot strike with shoes

In the pictures taken from Harvard of an Elite Kenyan runner's running form, the simple addition of footwear changed the strike zone of the runner.

According to Harvard Research, the heel strike running form is less desirable due to the greater effective mass acting on the foot and the rate of acceleration of force upon impact. 

We all know the basic formula Force = Mass * Acceleration. Here, the Force is the impact at the strike zone of the foot, the Mass is the amount of weight on the foot , and Acceleration is the deceleration of the foot upon impact.

Mass

The effect of heel strike running is the foot and lower leg come to a dead stop at impact while the rest of the body collapses on top of the knee thereby putting its weight on the foot. This equates to an effective mass of 6.8% of the total body mass acting on the foot.

The forefoot strike running although also comes to a dead stop upon impact, the heel and lower leg continue to fall. This equates to an effective mass of 1.7%.

Acceleration

The difference in deceleration of the foot does not differ significantly. However, the way the foot reacts to the impact affects the way the vertical momentum is converted upon impact.

In the heel strike, the vertical momentum of the lower leg is mostly absorbed by the vertical component of the collision force. Imagine a metal rod being dropped straight down.

In the forefoot strike, the vertical force is converted into a rotational momentum. Imagine a metal rod being dropped at an angle.

Force

The heel strike method thus leads to a rapid, high impact transient approximately 1.5 times your body weight within 0.05s of striking the ground if going at a slower pace but up to 3 times your body weight if going at a more rapid pace.

Imagine a hammer hitting your heel with 1.5 times your body weight with each step. Fortunately if you are a heel strike runner, it is more likely than not that you are wearing one of those overprotective shoes.These shoes make the heel strikes significantly more comfortable and less dangerous because they spread the force over a larger area of the foot and slow down the rate of deceleration thereby reducing the force acting on the foot.

Impact on feet Heel strike with Shoe

Impact on feet Heel strike without Shoes

The forefoot strike method thus leads to a smaller impact transient with a smaller effective mass and smoother transition of force. The same applies to midfoot strike on the most part.

Impact on feet Forefoot strike without shoes

Solution

One can't throw off one's braces and proclaim they no longer has use for them. It is strongly advised to introduce the new method of running gradually or risk more injuries. Reawakening and strengthening the muscles in your feet is a very important first step, but it is also important to take time to let the muscles rest.

Week 1
Try to walk around barefoot as much as possible around the house, do some calf raises, arch domes, and calf stretches.
Calf Raises: stand on one foot and try to go as high as you possibly can
Arch Domes: press your toes into the floor without curling them and raise your arch
Calf Stretches: stand on the edge of a stair with your forefoot and sink your heel as low as you can with your hand on a railing

Week 2-3
Walk around in your minimalist shoes, occasionally jogging for 1 minute to get a feel of the shoes. Increase jogging at most by 1 minute a day if you feel comfortable with the previous time interval. Continue to do Week 1's exercises.

Week 4-5
Start running in the shoes starting at 12 minutes, increasing the time ran by 2-3 minutes every other run if comfortable.

Week 6
Run easy four times this week. 25 minutes for for the first two runs and 30 minutes for the next two runs.

Week 7
Here on out feel free to increase distance ran by 10% each week. Remember to pay attention to your body and stop when experiencing any discomfort.