Science Summary: Getting There (Cardio or Weights Part 1)

In the next few summary posts, I’ll be giving the takeaway points from Alex Hutchinson’s Which Comes First, Cardio or Weights.  This book takes a look at many common questions asked in the fitness industry and pairs them with an answer backed by a published scientific study.  Overall, I’ve been very impressed with the scope of questions addressed by the book and the scientific backing for the claims it makes.  I do think the book is a bit much for casual reading which is why I’m writing this series.  I want to make the information readily available in a concise format.

All of the following questions are taken from this book and the answers are paraphrased from the authors words with my interpretations and thoughts added in.

— Scott

How long does it take to get in shape?

Short answer: Your body benefits from any kind of exercise immediately, but aesthetic results and long lasting changes take more consistent effort.

Long answer: Your central nervous system (CNS) will start to adapt from the very beginning as your brain learns how to recruit your body to perform the task at hand.  Whether this is lifting weights or running a mile, your body and brain learn how to do these things efficiently and they learn quickly.  Immediately following exercise, your body also processes blood sugar more effectively and insulin responses become more regulated.  For more lasting changes, the University of Tokyo published a study finding muscle strength increases after two months and muscle size increases after three months in study participants exercising four times per week.

Am I exercising enough?

Short Answer: More is almost always better but every bit helps your body in the long run.

Long Answer: A study by the National Institutes of Health found that light to moderate exercise in a group of 250,000 participants aged 50-71 reduced mortality rates by 30%.  If the exercise intensity was increased to include some vigorous exercise, mortality rates dropped by another 20%.  Another study conducted by the Lawrence Berkely National Laboratory has been following 120,000 runners since 1991 and found a very strong relationship between amount of aerobic exercise preformed, the intensity of the activity, and level of health determined by rates of disease.

Which should I do first? Cardio or weights?

Short answer:  If you’re looking for strength gains, do weights first.  If you’re looking for endurance gains, do cardio first.  If you want to maximize both, alternate daily between the two instead of combining them.

Long answer:  Our bodies adapt to the task at hand.  This means they tend to specialize which makes it difficult to be both a power lifter and a marathoner.  That being said, it is possible to achieve significant levels of endurance and strength at the when training properly.  Research has found your body is only able to focus on one specialization at a time and can not switch focuses quickly.  Because of this, when you start your workouts with weight training your body will go into strength training mode and the cardio that follows will not be as effective at training endurance.  The same goes for starting your workout with cardio, endurance gains are pronounced while strength gains are limited.  This does not mean that the second portion is wasted however, it simply will take longer to see results.  Derek Hansen, the head strength and conditioning coach at Simon Fraser University, recommends alternating daily between strength and cardio instead of both on the same day in order to maximize gains.

Can I get fit in seven minutes a week?

Short answer: Theoretically yes, but practically it’s going to much harder (and a bit longer than seven minutes).  It requires you to condense the effort expended in an hour long workout into a 7-10 minute workout instead and still isn’t a perfect substitute.

Long Answer: Interval training has been around forever and has been a tool used by professional athletes to achieve the next level of success.  The University of Ontario conducted a study comparing participants who performed 4-6 sets of 30 second sprints against participants who ran at a moderate pace for 30-60 minutes.  Each group trained three times a week for six weeks and the researchers found identical levels of fat loss and endurance gains in both groups.  The sprint group however achieved their endurance through muscle efficiency while the long distance group achieved endurance gains through cardiovascular efficiency.

Can exercise increase my risk of heart attack?

Short answer:  The increase in risk is extremely small.  When compared against the reduction in rates of heart disease associated with exercise, it is riskier to not exercise.

Long answer:  A study conducted by epidemiologist Donald Redelmeier observed more than three million marathon runners and found a rate of two deaths per one million collective hours of exercise.  Hutchinson compares this figure the hourly risk of being alive faced by the average 45 year old male.