Cardiovascular exercise or strength training?

Is cardiovascular exercise or strength training better for overall health and longevity? In this post, we talk around this subject and provide our answer. But first, some questions.

Do you want to maintain good health? Of course you do. And you want to be active? Unquestionably. How about remaining healthy and capable to a ripe old age? Yes!

Of course you can have all these things, right?

Well, yes. But only if you strike the right balance.

I’ve just finished a rather excellent book called ‘Molecular Exercise Physiology’. It sounds a bit heavy, doesn’t it? And it was in places, I’ll be honest. But most of it was digestible. One thing that struck me was the importance of two particular factors associated with exercise physiology. Let’s just refer to them as AMPK and mTOR for the time being, and I’ll explain what they are further on. For now, just be aware that they inhibit each other, yet both have essential roles in helping you achieve a healthy, active long life.

In this post, I discuss the challenge, a proposed solution and, in doing so, I’ll touch on some of the subject matter in that excellent book. It’s by no means a book review, but it might give you a sense of what’s in it.

Health, longevity and quality of life

What characterises good health, longevity and quality of life? How about this list:

1. A strong heart and good circulation.
2. The ability to do everyday activities without feeling breathless.
3. Being able to walk around a city all day or walk up a mountain.
4. Avoiding popping your clogs before it’s your time.
5. Resilience from falls and injuries.
6. Good posture and lack of aches and pains.
7. Strong, resilient bones.
8. Looking fit – upright, neither fat nor scrawny.
9. Avoiding being chair-bound or incapable into old age.
10. Remaining healthy and resilient into old age.
11. Good blood sugar control and insulin sensitivity – i.e., free from type 2 diabetes.
12. A robust immune system.
13. Maintaining a healthy weight.
14. The ability to exercise or be physically active.

It’s a bit of a random list, you’re thinking. But as a recipe for health, longevity and quality of life, you’d take it, wouldn’t you?

Actually, it’s not as random as it looks. Some of these things are associated with AMPK, some with mTOR and some with both.

Let’s find out a bit more.

What are AMPK and mTOR?

AMPK and mTOR are both kinases. It doesn’t matter too much what a kinase is. Let’s just say they are both molecules involved in physiological processes. And, to a large extent, those physiological processes oppose each other, as well as having opposing implications.

AMPK

AMPK is activated by increased levels of Adenosine Monophosphate (AMP) and Adenosine Diphosphate (ADP). You produce both AMP and ADP when you break down ATP, which is your body’s immediate fuel supply. ATP is broken down rapidly when you exercise. That means you activate AMPK when you exercise.

You also activate AMPK when your glycogen levels are low. Glycogen is the form in which your body’s carbohydrate is stored. Glycogen is depleted especially during extended periods of exercise.

Endurance exercise is particularly good at activating AMPK, mainly because of the above two factors, but also because it is uninhibited by mTOR, which is activated by resistance exercise. The practices of calorie restriction or fasting are also good at activating AMPK as they are going to deplete glycogen stores.

So what is AMPK good for? Well if you stimulate AMPK by performing endurance exercise, then you will

• Develop a strong heart. You’ll strengthen your heart better with endurance exercise than with other forms of exercise. That’s because your heart gets to squish a full ventricle of blood twice per second for thousands of seconds. It gets a good workout. With other forms of exercise, it doesn’t get put through its paces as much. For example, if you’re doing high-intensity interval training (HIIT) and puffing really hard, then your heart rate is going to be high. But your heart doesn’t get time to fill up, so it doesn’t get to practise the full squeeze. OK, so nothing to do with AMPK except that, if your goal is to stimulate AMPK, you’re better off using endurance exercise because it strengthens your heart. You don’t get that with either fasting or calorie restriction.
• Gain the ability to do everyday activities without feeling breathless. That’s because AMPK stimulates mitochondrial biogenesis and angiogenesis. In other words, it helps you manufacture new mitochondria and grow new capillaries. Additional mitochondria in your cells will help you use fuel more efficiently, and new blood vessels will help deliver oxygen to your muscles. Combine this with an efficient heart, and the result is that you don’t get out of breath doing everyday activities like climbing the stairs.
• Be able to walk around a city all day or walk up a mountain. What we’re talking about here is stamina. On these all-day adventures, you need to be able to keep going in the absence of a big meal. That means you need to be able to draw on your most abundant fuel supply – your body fat stores. AMPK improves your ability to oxidise fat and you become good at it. It enables metabolic flexibility – the ability to use either carbohydrate or fat as a fuel. Without the ability to oxidise fat, you will deplete your glycogen stores more quickly and require a carbohydrate refuel a lot sooner. Being able to oxidise fat will spare your glycogen and aid in the improvement of body composition when you are maintaining calorie deficit or parity.
• Reduce the probability of popping your clogs before it’s your time. Yep, that’s right. It has been shown that endurance athletes have a longer life expectancy than the average citizen. Interestingly, it is also well known that calorie restriction also increases life expectancy. In fact, there’s an extensive study on calorie restriction and good evidence that it increases lifespan. What do endurance exercise and calorie restriction have in common? AMPK.

Sounds good, doesn’t it? That’s the first four items of our 14-strong list dealt with. So, go on, get out there and get some cardiovascular exercise done!

mTOR

mTOR is activated by resistance exercise and amino acids. It combines the molecular signals produced by growth hormone, insulin, amino acids and resistance training to stimulate hypertrophy, i.e., muscle growth. That means if you do some weight training and chug down a protein and carbohydrate drink afterwards, you’ll strongly stimulate both mTOR and muscle hypertrophy. In fact, that’s the general practice of most athletes who want to build muscle and strength.

So, what is mTOR good for? Well, if you stimulate mTOR by performing regular resistance training and consuming sufficient protein, then you will

• Develop resilience from falls and injuries. That’s because you’ll be stronger. You’ll have better balance and be able to catch yourself from falling. And because your muscles will be conditioned, they will also be less susceptible to injury from everyday activities.
• Maintain good posture and have fewer aches and pains. Strength training will strengthen your postural muscles. Being able to carry yourself properly will stop you developing posture-related niggles and injuries, help you look younger and reduce stress from, for example, not being able to expand your ribcage to breathe correctly.
• Help you develop strong, resilient bones. Bone mass declines as you get older. This affects women more than men. As an example of the severity of this bone loss, incidences of leg breaks were found to be 50 times higher in 70-year old women than in 40-year old women. The pull of muscles has the most significant influence on the strength and integrity of your bones. While walking, because it is weight-bearing, may help strengthen the bones in your lower limbs, it will not help with your upper body. For that, you need to do resistance exercise.
• Looking fit – upright, neither fat nor scrawny. This is about aesthetics. It’s not vanity though, it’s a primal instinct. You want to look good, right? Chaps, do you fancy having a v-taper? Ladies, how about an attractive silhouette? Having superior tone will help you achieve these things.
• Avoiding being chair-bound or incapable into old age. Too many people end up in wheelchairs or using a frame because they are not strong enough to support themselves. For too many people, quality of life is reduced early because they are not able to perform straightforward activities. It doesn’t have to happen. Stay strong. Activate your mTOR by getting enough protein and performing resistance exercise.
• Remaining healthy and resilient into old age. This sounds similar to the ones above, doesn’t it? What we’re talking about here is muscle’s role in supplying protein and, particularly, glutamine, to the rest of the body. Muscle is your body’s protein and glutamine reservoir. If that reservoir is topped up, then you will be better able to replace dead cells, repair after injury or provide your immune system with the critical glutamine that it needs to function well. You’re going to come off better in the event of trauma or infection. You will reduce your chances of dying from those events.

Not only is muscle crucial for your health and wellbeing now, it is even more so as you get older. Sarcopenia – the age-related loss of muscle – has wide-ranging consequences that can severely impact quality of life and increase the risk of morbidity or even mortality. For a more detailed look at how to slow sarcopenia, take a look at our previous article on preserving muscle.

mTOR sounds pretty good too, right? Yep, and that’s the next 6 knocked off our 14-item list. So, get out there and start lifting weights!

So what’s the problem?

AMPK and mTOR both sound great, so what’s the problem? The challenge is that AMPK and mTOR tend to oppose each other. Not only do they inhibit each other, but the associated eating strategies also counter each other.

Here are the main points.

• Endurance exercise inhibits muscle growth. That’s because you’ll stimulate AMPK, and that will inhibit mTOR. Typically your body is in equilibrium, with muscle protein breakdown and synthesis taking place equally. With muscle protein synthesis switched off by AMPK, breakdown will dominate. You’ll waste. That means you’ll have a hard time gaining muscle if you do a lot of endurance exercise.
• Endurance exercise improves lifespan; mTOR reduces it. What!? mTOR reduces lifespan? Yep, at least in animals. In quite a few species actually. Just to be clear, there is no compelling evidence that bodybuilders, for example, have a reduced lifespan. But that’s not the same as saying mTOR does not reduce lifespan in humans. It just means the science hasn’t been done and so the evidence is not there. But given the number of species where mTOR does reduce lifespan, it wouldn’t be beyond belief to think that it does the same in humans.
• AMPK is stimulated by fasting, calorie restriction and energy depletion; mTOR is stimulated by feeding and energy sufficiency or, better still, an energy surplus.

So, does that mean you can’t have all the things in our original list of 14? Does that mean you have to choose some of them over others? Is cardiovascular exercise or strength training better for overall health and longevity?

We’ll answer that question shortly, but first, some good news.

The good news

Some of those things on the list of 14 you can have regardless of the type of exercise you do. That’s because all kinds of moderate or vigorous exercise will do the trick. Exercise will

• Improve your blood sugar control and insulin sensitivity. That goes hand in hand with a decreased risk of developing type 2 diabetes.
• Improve your immune response. There’s a caveat here though. High-intensity exercise or overtraining will reduce your immunity. For example, it’s been reported that a third of athletes completing a marathon will succumb to an upper respiratory tract infection in the two weeks following the event. That compares with 15% in the general population. In contrast, regular moderate exercise will improve your immune system. For more details, visit our previous post on strengthening your immune system.
• Help you maintain a healthy weight. That’s mainly because training helps you burn calories. But also because exercise will create better physiology, such as improved oxidation of fat.
• Maintain your ability to exercise and be physically active. That means it improves your ability to perform enjoyable activities such as dancing, gardening, hiking and, of course, playing sport.

So, at least you can gain some health and lifespan benefits merely by exercising. To be clear, though, you must do proper exercise to get the benefits. It’s not enough simply to increase your step count. Recommendations are 30-60 minutes a day (150 minutes per week) of purposeful moderate exercise or 20-60 minutes per day (75 minutes per week) of vigorous exercise.

A strategy to optimise AMPK and mTOR

So, what can you do about the counteracting effects and influencers of mTOR and AMPK? Is cardiovascular exercise or strength training the better approach? The answer is they both bring different benefits and I think there’s an approach that will optimise both even if it doesn’t maximise both.

First of all, if you want to maintain muscle and stay strong, you don’t have to train like a bodybuilder and eat massive amounts of food. So, a calorie surplus and intense weight training is not necessary if you just want to be strong and capable with good posture.

Second, if you’re eating, and getting protein in those feeds, you’re stimulating mTOR. You can’t get away from that. So even if your philosophy is calorie restriction, you’re still going to be stimulating muscle protein synthesis whenever you eat. If you do some resistance training to stimulate adaptation, then you’re going to be building muscle during those bursts of mTOR after feeding. You can take advantage of AMPK away from those feeding windows.

So, in other words, activate your mTOR some of the time and your AMPK the rest of the time. As long as you don’t overdo it with, say, excessive calorie restriction or daily marathons, your AMPK time is not going to waste your muscles. It’s not going to undo all the protein synthesis achieved during your mTOR time. That means you can reap the benefits of staying strong and upright without removing the beneficial effects of decent amounts of AMPK.

So, the answer to the question of whether cardiovascular exercise or strength training is better is that neither is better than the other. They’re both beneficial. Don’t choose one over the other, do both.

A health and longevity recipe

Here’s a list of things you could do to optimise your health, quality of life and longevity:

• Train with weights 2 to 3 times per week. Train the whole body as hard as you can. Short, sharp, intense.
• Include posture-related exercises and activities in your routine. That means doing posture improvement exercises, foam rolling and stretching. You might also want to try yoga and getting the occasional sports massage.
• Perform moderate-intensity cardiovascular exercise 4-5 times per week. Focus on endurance, keeping the duration between 30 and 60 minutes. If you do it fasted you’ll improve AMPK stimulation and fat oxidation adaptations.
• Keep your calorie intake at, or slightly below, maintenance levels. That almost goes without saying. If you consume more calories than you burn, i.e., above maintenance levels, then you’re just going to get fat. And being overweight brings with it a whole different set of problems. Eating slightly below maintenance will help you lose weight and stimulate more AMPK.
• Consume at least 20g of protein with every meal or snack and eat several times a day. You’re better off getting four feeds of 20g of protein per day than one feed of 80g or eight feeds of 10g. That’s because you stimulate muscle protein synthesis optimally at around 20g of protein. Below that (for example, at 10g) protein synthesis declines sharply. Above that, the amount of protein synthesis is not dose-dependent. That means you won’t get four times the protein synthesis by consuming 80g protein. Adequate and often would be the mantra when it comes to protein intake.
• Aim for a low fat, medium protein, high carb diet. It’s been shown that a diet of 15% fat, 35% protein and 50% carbs is better than a higher fat diet for preserving muscle when in a calorie deficit. Protein is filling and will help offset muscle breakdown. Personally, I’d reduce the protein a little and go for more carbs. There’s only so much protein you need to optimise muscle protein synthesis, whereas carbs provide additional benefits such as fibre, feelings of wellbeing and inhibition of muscle protein breakdown.
• Eat a balanced diet with lots of fruit and veg, pulses, wholegrains and sufficient protein. This has little to do with either AMPK or mTOR, but it will reduce your chances of developing a disease and improve your chances of living a long, healthy, active life. I can’t present a recipe for health and longevity without listing this!

The take-home message

If you’re a regular exerciser, then that’s great. You’re already doing a lot for your health. But if you only ever perform one type of exercise, then you’re not doing everything you could to optimise wellbeing and longevity.

Although genetics play a significant role in your ultimate health and lifespan, there’s a lot you can do to negate the influences of your genes and maximise your quality of life. Ideally, you’ll reap the rewards that come with both cardiovascular endurance exercise and strength training. Improve your odds: include both in your fitness regime.