This is a common question I often get asked by men in midlife who want to stay in shape, avoid chronic disease and have more vitality.
Cardio training should be secondary to strength training. If you're a man in midlife, you should prioritise strength training for long-term health and vitality - I've written about this in the blog Why Building Lean Muscle Mass Is Non-Negotiable For Men Over 40.
Once your strength training is in check, you can add cardio.
Not all cardio is equal, and our chosen type must depend on our goals.
How do you structure your cardio training?
Cardio Goal: Training for Endurance Events
If you plan to run a 5k, 10k marathon or compete in a triathlon, you'll need to train accordingly. This involves building endurance, increasing running efficiency, and learning to fuel your body for long-distance efforts.
It also requires a lot of time and high volumes of training.
Is It Healthy?
Endurance training comes with notable health benefits. Marathon runners, alpine skiers, and endurance cyclists often have excellent cardiovascular fitness and mitochondrial solid health (mitochondria are the energy generators inside our cells).
Their VO2 max scores, which measure the maximum amount of oxygen their bodies can utilise, are typically among the highest athletes due to their reliance on the aerobic energy system.
While actively training and competing, endurance athletes often enjoy better insulin sensitivity, a reduced risk of type 2 diabetes, and an improved lipid profile (lower LDL cholesterol and triglycerides, higher HDL cholesterol) even tho they often eat a diet high in carbohydrates.
However, while moderate endurance exercise benefits heart health, excessive endurance training can have negative cardiovascular effects.
Some of the adverse health impacts of endurance training:
Issues such as atrial fibrillation (irregular heartbeat), myocardial fibrosis (scarring of heart tissue), and an increased risk of sudden cardiac events have been observed in some endurance athletes.
You only need to look at the physiques of endurance athletes to see potential health issues. High volumes of cardio training break down muscle mass. Prolonged endurance exercise can place the body in a catabolic state where muscle breakdowns. High volumes of cardio increase levels of cortisol, a stress hormone that promotes muscle breakdown.
Many endurance athletes appear frail, with low muscle mass and bone density. They might also suffer from gut issues, nutrient deficiencies, hormone imbalances, mental health issues, insomnia, reproductive issues, and increased susceptibility to infections such as colds and upper respiratory infections.
When these athletes retire from their sport, they may quickly gain fat, become insulin resistant, and see increases in their cholesterol levels. This is often because they stop training, continue eating a high carbohydrate diet, and have very low muscle mass. This situation can lead to a metabolic imbalance and health issues.
Endurance Sports Approach for Men in Midlife
While endurance sports can benefit cardiovascular health, mental well-being, and overall fitness, it's important to approach them with a balanced and well-informed strategy.
For men in midlife who don't aim to compete in endurance sports, high-volume cardio is not the best approach for optimal health and longevity.
Instead, a balanced fitness regimen that includes strength training, flexibility exercises, and zone 2 cardio is generally more beneficial. This approach helps maintain muscle mass, supports bone health, and improves overall metabolic function.
Cardio Goal: Training for Fat Loss & Health
When it comes to fat loss, cardio has its place, but it's only sometimes the most efficient tool, especially if you're relying solely on cardio.
Excessive cardio can lead to muscle breakdown, which isn't ideal because muscle is metabolic – it helps drive your metabolism. The more muscle mass you have, the more efficient your metabolism will be.
Muscle is often referred to as the organ of longevity because it offers a multitude of health benefits, especially as we age. If you're short on time, prioritising strength training can provide the best health and longevity benefits.
Zone 2 Cardio
If you've got time for cardio and want to use it to “burn fat”, then Zone 2 cardio is a good option.
Zone 2 cardio involves aerobic exercise performed at a moderate pace, where your heart rate is elevated but not overly so.
It's often dubbed the "fat-burning zone" because, at this intensity, your body efficiently uses fat as a fuel source. This type of training is typically done at 60-70% of your maximum heart rate and can be sustained for longer durations.
In simple terms, it's an effort level where you can comfortably hold a conversation while working out.
Health Benefits:
Improved Cardiovascular Health: Zone 2 cardio enhances heart health, lowers resting heart rate, reduces blood pressure, and decreases the risk of heart disease.
Enhanced Fat Metabolism: Training in this zone optimises your body's ability to burn fat, which can lead to improvements in overall metabolic health.
Improved Mitochondrial Function: Zone 2 cardio increases the number and efficiency of mitochondria in muscle cells, boosting endurance and energy production.
Better Insulin Sensitivity: Regular Zone 2 training enhances insulin sensitivity, aiding in blood sugar regulation and reducing the risk of type 2 diabetes.
Increased Fitness Levels: This type of cardio builds a solid aerobic base, improving endurance and stamina for daily activities and more intense physical exertion.
Mental Health Benefits: Zone 2 cardio can help reduce anxiety, improve mood, and promote overall mental well-being.
Recovery and Longevity: It can serve as a form of active recovery, promoting blood flow and aiding in recovery without excessive strain on the body.
Consistent moderate-intensity exercise has been linked to increased health span and improved quality of life with age.
How to Perform Zone 2 Cardio:
Zone 2 cardio, also referred to as low-intensity steady-state exercise (LISS), is best performed at a pace where you can maintain a comfortable conversation. It's not about pushing yourself hard or getting out of breath; it's about sustaining a low-intensity effort that targets the "fat-burning" energy system.
When the intensity goes up, the body demands more energy, which requires it to shift from “fat burning” to glycogen burning - it’s a different energy pathway that’s not as effective for fat loss.
Incorporating Zone 2 cardio into your routine can offer a balanced approach to improving both aerobic fitness and overall health, which is particularly beneficial for men in midlife aiming for long-term well-being.
Performing 2-3 x 45-60-minute Zone 2 cardio sessions per week is enough to see the health benefits.
Cardio Goal: High-Intensity Intervals & Health
At the opposite end of the cardio spectrum are sprinters whose bodies showcase low body fat, strong and powerful muscles, and high muscle mass. These athletes focus on low-volume, high-intensity cardio, often called sprint intervals.
If you observe sprinters closely, you'll notice that those specialising in 100m, 200m, and 400m sprints boast strong, lean physiques with low body fat percentages.
All these sprint events typically last less than 60 seconds, pushing athletes to operate at high-intensity levels of 9-10 on a scale of 1-10, also known as Zone 5.
Health Benefits:
Improved Cardiovascular Health and Fitness: Regular high-intensity training enhances heart function, reduces blood pressure, and improves cholesterol levels, thereby lowering the risk of cardiovascular diseases. Zone 5 training significantly boosts VO2 max, indicating superior cardiovascular fitness. This metric reflects the maximum amount of oxygen your body can utilise during intense exercise.
Increased Caloric Burn: High-intensity intervals elevate your metabolic rate for hours post-workout, resulting in additional calorie expenditure due to EPOC (excess post-exercise oxygen consumption).
Improved Insulin Sensitivity: High-intensity training enhances glucose utilisation and storage, reducing insulin resistance and the likelihood of type 2 diabetes.
Enhanced Fat Loss: While carbohydrates serve as the primary fuel source during Zone 5 training, the intensity stimulates overall fat oxidation throughout the day.
Muscle Adaptation and Growth: High-intensity intervals recruit fast-twitch muscle fibres, which are vital for strength and power development.
Hormonal Benefits: Intense exercise prompts the release of growth hormones, facilitating muscle repair, fat metabolism, and recovery.
Enhanced Mental Toughness: Pushing through the intensity of Zone 5 training builds mental resilience and fosters a sense of accomplishment, contributing to overall mental well-being.
Zone 5 cardio training delivers myriad health benefits, improving cardiovascular fitness, calorie expenditure, insulin sensitivity, and mental fortitude.
However, it's demanding and may pose challenges as we age. Sustaining Zone 5 cardio long-term requires careful consideration of its impact on overall health.
Some of the adverse health impacts of Zone 5 training can include:
Increased Risk of Injury - The high-intensity nature of Zone 5 training puts immense stress on muscles, tendons, and joints, raising the risk of strains, sprains, and overuse injuries.
Cardiovascular Strain - Exercising at near-maximal effort can strain the cardiovascular system excessively, potentially leading to cardiac issues such as arrhythmias or myocardial stress.
Metabolic Stress - Zone 5 training significantly elevates levels of stress hormones like cortisol, which, when chronically elevated, can contribute to metabolic imbalances and hinder recovery.
Overtraining: Excessive Zone 5 training without adequate recovery can lead to overtraining syndrome, characterised by fatigue, decreased performance, mood disturbances, and increased susceptibility to illness.
Impact on Hormonal Balance - Prolonged high-intensity exercise may disrupt hormonal balance, potentially leading to issues such as suppressed immune function, disrupted sleep patterns, and reproductive hormone imbalances.
Increased Oxidative Stress - Intense exercise generates reactive oxygen species (free radicals), leading to oxidative stress, which, if not countered by antioxidants, can contribute to cellular damage and inflammation.
It's essential to approach Zone 5 cardio training cautiously, ensuring adequate rest, recovery, and periodisation to mitigate the risk of adverse health implications. Balancing high-intensity sessions with lower-intensity activities and incorporating restorative practices can help maintain overall health and well-being.
How to Perform Zone 5 Cardio:
Mainstream fitness often misinterprets high-intensity training, leading to confusion about true Zone 5 workouts.
Genuine high-intensity cardio entails exerting a 9/10 effort over a brief, intense period—for instance, sprinting at maximum intensity for less than 60 seconds followed by ample rest (5+ minutes) between intervals.
During Zone 5 training, the body heavily relies on anaerobic energy systems, rapidly depleting muscle glycogen stores and ATP-PC. Adequate rest intervals enable partial replenishment of these stores, allowing you to sustain subsequent intervals at high intensity.
Insufficient rest compromises energy replenishment, diminishing the intensity of subsequent intervals. Thus, maintaining the required 90-100% maximum effort for effective Zone 5 training becomes challenging.
Remember, any activity exceeding 60 seconds or lacking adequate rest between intervals isn't genuine Zone 5 training.
Midlife Maverick Cardio Recommendations
Time is often the key consideration when it comes to training, especially for men in midlife with a list of responsibilities.
Building and maintaining muscle mass needs to be the primary focus because it offers the best bang for your buck when it comes to health and vitality.
Cardio can then be scheduled around your strength training session if you have the time to add it in. Ideally, doing 2-3 x 45-60min of Zone 2 per week is best, but if you're short on time, do less. Find what's manageable and sustainable for you.
Doing 1-2 Zone 5 sessions per week can also be effective for health and wellness if you have the capacity and time to do so.
A combination of Zone 2 and Zone 5 is possible. You can even do them both in the same session, but you'll have to do Zone 2 first and then do Zone 5. An example of this would be doing 45mins of Zone 2 followed by 5 x :20sec sprints with 2mins rest between each interval.
Everyday Cardio
Walking to work, taking the stairs, riding your bike, and playing with your kids are cardio activities.
There are often opportunities to add more cardio into our daily activity without the need to schedule specific cardio training sessions.
Strength training also targets the cardiovascular system. Your heart’s lungs work hard to pump blood, oxygen and nutrients to the working muscles.
Additional cardio sessions can offer health benefits if you have time. However, we need to be mindful of overtraining, rest, recovery, sleep, nutrition, stress, and other lifestyle factors.
More isn't always better.
It's about creating a sustainable training program that supports your lifestyle, gives you energy, and makes you feel amazing.
You don't need to smash yourself into the ground with high-intensity workouts or train seven days a week to see health benefits. Training like this can have negative impacts on your health.
If you'd like to learn more about the health and longevity benefits of Zone 2 cardio, make sure to check out this podcast with podcast with Iñigo San Millán