How Much Rest Time Should You Take Between Resistance Training Sets?

 

One of the most common questions about weight training aka resistance training is how long should you rest between each exercise set.     If you take a look at the relevant research concerning this topic there are some good answers.

For a long time, researchers believed that shorter rest periods were better for increasing muscle size which was thought to occur because of increased levels of metabolic stress by not allowing complete recovery.    However, research done in 2015 shows that using longer rest periods actually results in better results for both increased muscle size and increased muscle strength.     It is thought that this occurs because longer rest periods allow a higher training volume (more repetitions of each exercise).

 Another aspect to consider is whether most of your workout uses compound exercises (compound exercises use multi-joint exercises using more muscle mass such as a chest press vs a pec dec or pull-up vs an Lat Pullover).      In a 2012 study researchers found that with shorter rest periods workout volume decreased for both single-joint and multi-joint compound exercises.       However, the decrease in volume in workouts with short rest periods tended to be significantly greater with multi-joint compound exercises vs single-joint exercise (29% reduction in volume with multi-joint as compared to 15% with single- joint exercise). So for strength routines focused on compound, multi-joint movements increased rest time is probably a good idea.

Another study which looked at the effects of rest interval length on training volume discovered another important item:    reduction in training volume occurs mainly between 1 and 2-minute rest periods.    The percentage difference between 2 and 3-minute rest periods is much smaller, except when doing 5 or more sets of an exercise.     So, for people doing 3 – 4 sets per exercise, 2 minutes is a good rest interval, but if doing 5 or more sets you should probably extend the rest interval to 3 minutes.

Another important piece of information is that recreational lifters who self-determine rest periods tend to rest just under 2 minutes between sets meaning that for most lifters doing 3 to 4 sets of several exercises whose goal is increased muscle size and strength you probably do not need to time your rest intervals and can go just go by feel.

 Timing rest intervals becomes more important for advanced resistance training such as Power Lifting and Bodybuilding, but for most of us we can just go by how we feel!

The Facts on Safe Sun Exposure and Vitamin D - Part 2

 

Optimizing Vitamin D through Safe Sun Exposure

By following sensible sun exposure rules, including making sure you do not get burned, you can maximize the benefits and minimize the risks of skin damage that could lead to skin cancer. Overexposure, not completely avoiding the sun, is the real issue for increasing your risk for skin cancer.  At the same time, optimizing vitamin D through regular sun exposure can decrease your risk of many forms of cancers that are far more common than Melanoma which is the deadliest form of skin cancer.

 So how much sun exposure is enough?

 The answer depends on your skin type, time of year, time of day, and where you are located!  The closer you are to the equator the less time you need in the sun because the sun is stronger and more UVB rays hit your skin (UVB is the key to Vitamin D).     Depending on your location time of year can be very important.   For example in the Northeastern US you cannot get enough sunlight exposure during winter to max sufficient amounts of Vitamin D for optimal health (one of the reasons tend to get sick more in the winter).  Time of day is also important.  Ideally mid-day sun provides the highest level of UVB light BUT you also need much less sun exposure and it is much easier to burn! 

 As mentioned above your skin type is also important!  There are technically 5 skin types as it relates to sun exposure times: Type I - White; very fair; red or blond hair; blue eyes; freckles Type II – White; fair; red or blond hair; blue, hazel, or green eyes Type III – Cream white; fair; with any eye or hair color; very common Type IV – Brown; typical Mediterranean Caucasian skin Type V – Dark Brown; mid-eastern skin types Type VI – Black

 If you are skin type 1 to III, you will produce vitamin d more quickly than if you have skin type IV to VI.      A simple rule is to obtain half the sun exposure it takes your skin to turn pink (NOT BURN).     This will tend to optimize benefits without risks.   The more skin you can expose the better!   Once you have been in the sun this long you should cover up – actually covering up is ideal versus using sunscreen.    So wearing hat shirt and pants made out of a light but UV blocking material is ideal if you are going to be outside longer than half the time it would take for your skin to turn pink.

 According to the national Institutes of Health, between five and 30 minutes of sun exposure to your unprotected face, arms, legs or back between the hours of 10 a.m. and 3 p.m. two to three times every week is enough for your body to produce all of the D3 it needs. So for extremely fair people during peak summer or live close to the equator just 5 minutes of mid-day sun is all it takes, but for a person with dark skin who lives farther from the equator it is probably more like 30 minutes.    Now the key is NOT to burn so start with less time and gradually increase it!

The Facts on Safe Sun Exposure and Vitamin D - Part 1

 

If you are confused about whether exposure to the sun is good or bad or somewhere in the middle – you are not alone!   There is a ton of conflicting advice and information being given on Sun Exposure.   On the one side we are being told to completely avoid all sun exposure and wear heavy duty sunscreens at all time, and on the other being told that sun exposure is vital and good for us.   

 As always, the real answer is somewhere in the middle, and it is critical to evaluate the validity of information you receive based on the source and if they have a commercial stake in the information they give you.  

 For example, it is not at all surprising that sunscreen manufacturers are pro sun screen and push the concept that everyone should wear it all the time to insure they do not get skin cancer, but we know they have a vested commercial interest so should use some judgment evaluating information from these sources.    And yes there is information suggesting that many sunscreens contain chemicals that can be harmful to your health.   It is important to use sunscreens that do not contain toxic ingredients and do block both UVA and UVB rays. For a great guide check out this article by Dr. Mercola:  http://articles.mercola.com/sites/articles/archive/2014/06/04/ewg-sunscreen-guide.aspx

 The fact is that this issue is not so simple as “authorities” would have you believe.  For example, in this research article (Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden Cohort) that studied all-cause mortality in 29,518 Swedish Woman the conclusion was that avoiding the sun can actually be as dangerous as smoking when it comes to cancer risk and overall mortality risks. Woman who avoided the sun had a much shorter life expectancy than those who got the most sun.   This really challenges the conventional wisdom on sun exposure.   It is also important to state that it is all about dose and your personal genetics meaning that the amount of sun you are exposed to and your personal genetics are very relevant here!

 Improving Vitamin D Status is a Key Benefit of Proper Sun Exposure

 Sun exposure increases the body’s production of Vitamin D and does so in a way that is quantitatively and qualitatively different and superior to supplemental Vitamin D.    When the body produces Vitamin D from sun exposure it simply will never produce too much Vitamin D and this is not the case with supplementation.    In addition, there are other benefits to safe sun exposure in addition to Vitamin D production.   Proper sun exposure can and does help treat several skin conditions such as psoriasis, vitiligo, atopic dermatitis, and scleroderma.   In addition, sun exposure protects against and suppresses the symptoms of multiple sclerosis, helps relieve fibromyalgia pain, helps treat seasonal affective disorder, enhances mood and energy by stimulating the release of endorphins, and helps synchronize biorhythms and melatonin production.

 The Health and Medicine Division of the National Academies of Sciences, Engineering, and Medicine have reported an association between vitamin D and overall mortality risk from all causes, including cancer.   However, supplementation studies have been all over the map in terms of showing a positive relationship between boosting Vitamin D status and incidence or mitigation of disease.    Since we know for sure that the human body was designed with the specific capability of producing Vitamin D from sun exposure and we know that Vitamin D levels are crucial for optimizing health it seems quite likely that production of Vitamin D through sun exposure is the ideal if it can be done safely.

There is a lot of positive research on Vitamin D and cancer prevention and treatment, heart disease prevention and treatment, etc. showing that optimizing Vitamin D is a good prevention strategy.

 Vitamin D affects almost every cell in your body, which is one of the reason’s it affects so many different disease states.

Vitamin D from Sun Exposure and Health

There have been many studies done on average vitamin D levels and the vast majority of them have found that at least half of the U.S. population has inadequate levels.

Vitamin D is not really a vitamin – rather it is a steroid hormone that your body is designed to create through sun exposure, not from your diet. While some foods do contain vitamin D it is nearly impossible to get all the vitamin D you need from dietary sources alone.

The U.S. Surgeon General American Academy of Dermatology recommend complete and total sun avoidance in order to prevent skin cancer, and there is no question that overexposure to sun can and does cause skin cancer at some level.    However, sun avoidance has been shown to increase your risk of death from all causes substantially so this recommendation does not make the most sense.

 Stay tuned for Part 2 Next week and learn how to optimize safe sun exposure based on your skin type, where you live and time of year!

Can Dancing Improve Mental Function?

 

The short answer is YES!  It is common knowledge that aerobic exercise and resistance training can both help prevent decline in mental function as we age – but there is something particularly potent about dance exercise.

A recent study at Colorado State University looked at 174 people in their 60’s and 70’s and divided them into four groups who met three times a week for six months.   

One group did brisk walking.

Another group walked and took a dietary supplement.

A third group did stretching and balance exercise.

The fourth group learned new dances in hour long group dance sessions.

Researchers did scans to examine all participants brain pre and post study.   They found that people who did brisk walking slowed down the breakdown of the white matter in their brains.

But only one group significantly improved the amount of white matter in the fornix of their brains – the dancers.    White matter is found in the deeper tissues of the brain and contains nerve fibers coated with a myelin sheath (like insulation covering wires)

The fornix of the brain is located in an area of the brain called the limbic system and is involved in cognition, memory, emotion and sexual responses.