HIGH-INTENSITY INTERVAL TRAINING (HIIT) is a technique that has been used extensively to train athletes as well as for improving fitness and outcomes for people with medical conditions ranging from diabetes to heart disease. HIIT typically involves six to 10 short duration (10-60 seconds), super-high-intensity efforts (all-out or near 100 percent heart rate or VO2 Max) with a longer rest bout in between. Overall, HIIT is considered safe and effective, but is it better compared to moderate-intensity training for improving fitness and triathlon race performance?
As triathletes and consumers of triathlon products and media, we rely mainly on the word of manufacturers, athletes, and coaches to make decisions about the intensity and frequency of training. If there were no scientific literature available, then those sources would be appropriate. But over the past 30-40 years, there has been a lot of research on moderate intensity aerobic training and HIIT. The purpose of this article is to provide a brief overview of the scientific literature evaluating HIIT and advice about its use.
Fortunately, several systematic reviews (studies that objectively evaluate many individual studies and draw a conclusion on the overall effectiveness of a technique) have already been performed that have examined HIIT. Five recent reviews
Have you felt the signs of aging and lost much of your performance? Want to stave off the loss of muscle and lung capacity but would like to still do some fun athletic events? Climbing stairs painful and you can’t catch your breath? If you reached the grand age of 50 or more you’ve experienced a loss of muscle and lung capacity and gained extra pounds around your waist. If so you are not alone.
Aging is not lost youth, but a new stage of opportunity and strength.
Let’s explore what’s probably happening as you age (or if you’re young what you might expect). Then let’s see what can be done using three exercise variables that anyone can do; from athlete, weekend warrior or someone who just wants to keep fit and active.
Aging Facts (face the truth)
Skin loses its elasticity and becomes drier as oil glands slow their production.
Fingernails grow more slowly.
Hair thins, and there’s more gray hair as pigment cells are reduced.
Compression of joints, including spinal discs, causes a loss of height. By age 80, the loss of 2 inches is common.
Somewhere around age 55, high-frequency sounds start becoming harder to hear.
By age 50, most people need reading glasses as the eyes’ lenses become less flexible, impairing the ability to focus on anything close up.
Changes occur in the menstrual cycle before it ceases.
Sleep time typically becomes shorter, and the quality of sleep decreases. Waking often during the night is common.
Bone minerals are lost, resulting in more fragility.
The basic metabolic rate slows down, often resulting in weight gain— mostly fat
(List from Joe Friel; Fast After 50: How to Race Strong for the Rest of Your Life)
Aging Athletes (its the same for non-athletes too)
The symptoms of aging that concern athletes and non-athletes include:
Aerobic capacity (VO2max) declines.
Maximal heart rate is reduced.
The volume of blood pumped with each heartbeat decreases.
Muscle fibers are lost, resulting in decreased muscle mass and less strength.
Aerobic enzymes in the muscles become less effective and abundant.
Blood volume is reduced.
(List from Joe Friel; Fast After 50: How to Race Strong for the Rest of Your Life)
What Can You Do to Slow Down Aging
Obviously volumes are written about the science of aging. I know because I’ve read a ton about it. I finished my first Ironman triathlon at age 50. Thankfully I’ve completed a total of 15 but the last 4 were not pretty, walking the complete marathon. Currently at age 59 I want to continue racing for a long time. In 2014 I suffered a substantial decline in my performance even though I trained longer than at any time in my career. That year marked the first year of a series of injuries that put the brakes on me in 2015 with the surgery of a torn meniscus and then a major bike crash ending in another surgery.
I’ll be writing more blogs on what to do to overcome your rapid decline in aging and if you’re an athlete, how to increase performance or at least maintain competitiveness in the future years.
This is post is dedicated to understanding three exercises that are a must for anyone with the desire to improve their health past age 50. My decline in my race performances were because I quit doing these because they always lead to injury. Now I understand why.
Science confirms that as you age your aerobic capacity (VO2max) declines. What’s that and why is it important for you to slow down its’ decline? Aerobic capacity is simple. You deal with it as you exert any harder effort. It’s the amount (volume) of oxygen that your body can carry to a working muscle over a given amount of time. You see the decline and explanation with this example. Ever see a young person bound up stairs and not hardly be breathing hard at the top and someone older had to labor up them slowly and have to stop and catch their breath at the top? A younger person simply can supply more oxygen to the working muscle.
You can guess why anyone who is aging would want to increase their aerobic capacity. It will allow for better body function and produce more output of activity with less effort because you’ll be able to supply more oxygen to the working muscle.
The aerobic capacity decline is influenced by the other five symptoms of aging athletes and non-athletes.
The 3 Exercise Types to Improve Aerobic Capacity
Anyone, athletes and non-athletes, would benefit from improving their aerobic capacity. You may be a mom who doesn’t work out but would like to get rid of some excess fat and be more active. If you’re a serious athlete you want to improve your VO2Max (aerobic capacity) so you can race faster.
There are many research studies that confirm that as athletes (or non-athletes) age they quit doing as much high-intensity interval training(HIIT) and lose aerobic capacity. Yet in other studies of older high competitive athletes they continued to perform HIIT as a regular part of their training and maintained their higher VO2Max.
The most accurate way to determine your VO2Max is going to a lab and having a test done. A simple way to estimate your VO2Max is by the following formula:
For me: my most recent maximum heart rate running was 170. My lowest resting heart rate is 55. Therefore my VO2Max is 15 x (170 / 55) = 46.3.
You can see I have the aerobic capacity of 30-39 year old non-athletes, effectively making me 20 years younger than an average person. The test is a way to determine if you are actually improving with your fitness program.
1. What is a HIIT workout for an athlete?
According to Joe Friel, “When you perform intervals, the absolute intensity, the duration of the repetitions, the number of repetitions, and the duration of recovery between intervals must be only slightly more challengingthan your estimated current capacity for physical stress.”
If you’ve not done these in a while you have to take a cautious approach as you begin this type of training. They are stressful and can cause injury. It’s best to start with no more than 3 intervals of 3 minutes each going hard as described in the subsequent paragraph. The rest period in between intervals is no shorter than 90 seconds (1/2 the interval length) and not longer than 3 minutes (the length of the interval) to receive the maximum benefit.
They need to be done after a sufficient warm up period of not less than 15 minutes but better after 30 minutes. At the conclusion of the workout it’s wise to have a good cool down and stretch period.
Then depending on your fitness level you may need a week or longer recovery period before doing them again.
If you’re a runner then you’d run hard slightly less than at a pace that you could only sustain for 5 minutes. Never start out to hard and have to ease up at the end. It’s better to be able to go slightly harder at the end. You do the interval in your sport. For me as a triathlete I do them in each discipline; swimming, biking and running.
What is HIIT for a non-athlete?
It would be the same personal intensity, i.e., an effort slightly less than what you could maintain for 5 minutes. Yet for you, especially if you’re just starting out after a long layoff but feel your personal fitness would allow you to go this hard, the length of the interval might only be 30 sec to 1 minute instead of the 3 minutes mentioned above. Your recovery time would be the same amount of time as the interval. Only do three to start. As you begin to gain aerobic fitness you’ll be able to increase the duration of the interval with less recovery in between. In time you’d be able to increase the number of intervals.
Like with athletes, rest and recovery in between these kind of sessions is a must.
A typical HIIT for a non-athlete my be a step aerobic class, body pump or strenuous water weights in a pool. Anything that would elevate your heart rate to those levels mentioned.
2. Lactate Threshold Exercise
Okay I know these terms may be foreign to a non-athlete but it really describes the exercise well. Lactate is what the body burns during exercise. The harder the exercise the more it burns. It is mixed with oxygen to provide the muscle energy to contract and do it’s job. At a certain point though, the toxic waste by product of the lactate that was used as fuel is so great the body can’t remove it and you get a burning and stinging muscle. Ouch! The pain is because the lactate is acidic. Lungs hurt too. That is your lactate threshold. It’s easy to determine because of how you feel although testing in a lab is more accurate. For most non-athletes that simply is not needed.
Lactate threshold exercise is the intensity at about 95% of your threshold pace; that which you’d begin to feel a burning sensation in your muscles and lungs. The intervals here are way shorter. In fact, even if you are an athlete you may only want to go 5 minutes cumulative at this intensity. It may be 10 x 30 sec intervals with a full 30 sec rest in between or perhaps 5 x 1 minute intervals with a full minute in between.
Once again caution is warranted. Only attempt these if you feel fit enough to go this hard. If you feel any stress or unusual pain, stop immediately and seek help. Also, recovery is a must to overcome the tremendous stress your body is under.
What these do is increase your body’s tolerance to lactate and these will also improve aerobic capacity.
3. Weight Training
“Ugggg” you might have sighed if you’re a non-athlete. As you age you simply lose muscle mass. When this happens over time that leads to less hormone capacity and function and that leads to a loss of metabolism and fat gain, mostly around the mid-section.
Weight training needs to be done under the watchful eye of a professional if you’ve never done it before.
There are three types of weight training. First you lift in sets (2 or 3) with reps between 8-15 with less weight. The second kind is lifting in sets (2) with reps between 4-6 with more weight.
Weight training needs rest and recovery in between sessions. That is where the muscle is repaired and in grows. Many people need weight training to keep what muscle mass they have. The more lean muscle you have the more fat you burn because of improve metabolism and hormone function.
A third type of weight training is called functional strength training. It’s usually done with no weight or very little weight other than your body mass. It’s like sit ups and push ups. Or even one legged routines. Pilates and Yoga fall under this category.
Big Big Caution
I’ve not gone into any detail about the risks associated with HIIT or weight training. The risks are primarily with the greater chance of injury. If you’ve had a history of heart problems, these three, while beneficial, needs to be under the care of a medical or exercise professional.
The reason many aging athletes and non-athletes stop these activities is due to many factors; too hard, not enough time and even a belief that it is not needed. But the fact remains, they are needed to stay youthful, to increase and maintain aerobic capacity, lean muscle and reduced fat. I believe, looking back now, because I quit doing these as much as I needed and stuck with low intensity and high volume, I became injured running hard intervals. I quit doing any weight training because it was boring. My aerobic capacity I can see now from my training logs has been in decline.
I highly recommend you seek the advice of an exercise professional, coach or your doctor before doing any of these three types.
Many people who consider training for a triathlon, Ironman, or other long distance event are hesitant to commit for fear of losing hard-earned muscle. If you are one of these people, fortunately there’s good news. Incorporating heavy lifting into an endurance training regimen along with a diet high in protein may help athletes reduce unwanted muscle loss (1).
Why traditional endurance training can cause muscle loss
The idea that endurance-style training will cause muscle wasting is not unfounded. After all, the striking difference in the musculature of an Olympic marathoner and sprinter is clearly a consequence of the training tactics used to achieve two immensely different goals.
The goal of an endurance program is to improve stamina, and this type of training typically results in muscle loss for two reasons. First, endurance exercise activates pathways that help the body become better at using energy to go further rather than pathways that trigger muscle building (2). Second,endurance exercise can quickly burn through carbs and fat, forcing the body to breakdown muscle to help meet energy needs (2-4).
So how can muscle loss be prevented if endurance training overrides the body’s muscle building systems and at the same time contributes to muscle breakdown? The key is to strategically design anendurance program that includes heavy lifting, as well as a nutrition program that meets calorie needs while including the right amount of high quality protein.
Training to prevent muscle loss
The key for preventing muscle loss is to follow a training program that incorporates both heavy weights and endurance training. The type of exercise you do tells the body how to adapt. If you trained strictly for endurance without adding weights, you would build stamina but would sacrifice muscle size, strength, and explosive power. If you trained only using weights, you would build muscle mass, strength, and power, but would sacrifice stamina.
Therefore, it’s critical to keep your main goal in mind when planning how much of each type of exercise to do. There are diminishing returns to having a lot of muscle, which is heavy and requires more blood flow, oxygen, and energy to maintain and cool during exercise. However, muscle provides power and strength, which can mean the difference between first and second place. The key is to design and follow a program that fits your goal. If you’re an elite endurance athlete, prioritizeendurance training and include one or two heavy lifting sessions per week. If you’re more of a recreational endurance athlete afraid of losing muscle, you may choose to include heavy lifting as often as three times per week.
In addition to balancing endurance sessions and weights, a well-planned training program should be “periodized” to prevent heavy lifting from interfering with endurance performance during racing season. A periodized program breaks up a training period into blocks of time, changing the type, amount, intensity, and duration of exercise within those blocks of time as an event approaches. Because heavy weight lifting can cause soreness and interfere with the quality of endurance sessions, it’s best to lift more often in the off-season and taper down during in-season. For example, an athletemight lift heavy three times per week in the off-season to activate muscle building pathways and gain strength, and then maintain gains by lifting just once or twice a week leading up to an event.
Nutrition to prevent muscle loss
Along with a well-planned training program, incorporating the right nutritional strategy is essential for preventing muscle loss while endurance training. Special attention must be paid to make sure that protein and calorie needs are being met.
Protein serves as both a trigger for activating muscle building pathways, as well as the main substrate with which muscle is made. To ensure that muscle synthesis matches or exceeds breakdown, at least 1.2 to 1.7 grams of protein per kilogram of body weight should be eaten daily (80 to 120 grams for a 150 pound person) (5).
Protein timing and quality should also be taken into consideration. Meals consisting of 20 to 40 grams of protein should be consumed at regular intervals at least three to four times throughout the day, with one such meal being positioned strategically right before and after a workout (6, 7). Whey protein is the best type for consuming pre and post-workout because it’s high in branch chain amino acids (BCAAs), which are most effective for stopping muscle breakdown that occurs during extended exercise, as well as for promoting muscle growth and repair after exercise (9).
Getting sufficient calories and carbohydrates is also important for preventing muscle breakdown. Meeting these needs will ensure that the body has adequate fuel, in turn sparing muscle from being broken down and used for energy (2, 4). For endurance athletes with the goal of losing body fat during training, research shows that protein should be increased to as high as 1.8 to 2.7 grams per kilogram of bodyweight to offset muscle loss (7).
Don’t let fear of losing muscle stop you from training for an endurance event. When training and diet are done right, you can prevent unwanted muscle loss while building stamina and strength to beat out the competition.
1) Daniel R Moore et al. Beyond muscle hypertrophy: why dietary protein is important for endurance athletes. Applied Physiology, Nutrition, and Metabolism. 10.1139/apnm-2013-0591
2) Tarnopolsky M. Protein requirements for endurance athletes. Nutrition. 2004 Jul-Aug;20(7-8):662-8. Review.
3) Howarth KR et al. Effect of glycogen availability on human skeletal muscle protein turnover during exercise and recovery. J Appl Physiol (1985). 2010 Aug;109(2):431-8. doi: 10.1152/japplphysiol.00108.2009. Epub 2010 May 20.
4) Nutrition and athletic performance. Joint Position Statement, American College of Sports Medicine, American Dietetic Association, and Dietitians of Canada, 2009.
5) Phillips SM, Van Loon LJ. Dietary protein for athletes: from requirements to optimum adaptation. J Sports Sci. 2011;11(Suppl 1):S29–S38. [PubMed]
6) Willoughby DS et al. Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength. Amino Acids. 2007;11:467–477. doi: 10.1007/s00726-006-0398-7. [PubMed] [Cross Ref]
7) Phillips SM et al. The role of milk- and soy-based protein in support of muscle protein synthesis and muscle protein accretion in young and elderly persons. J Am Coll Nutr. 2009 Aug;28(4):343-54.