How to adjust your cardio workouts for weight loss, Cardiovascular Health & Longevity

Cardiovascular training has gone through quite the identity crisis over the past few decades. When I first began personal training in 1998, it was the undisputed champion of fat loss and general health programming. The Polar heart rate monitor was our go-to cardiovascular tracking tool and we used it to monitor clients staying in their ‘fat burning zone’ during workouts to get the most bang for the buck out of their time in the gym and their results. Then in the early 2000s came the strength revolution—where cardio was pushed to the back burner in favor of heavy lifting, metabolic resistance circuits, and HIIT (High Intensity Interval Training). But in 2025, cardio programming is seeing a clear resurgence. Thanks to advancements in longevity research, wearable tech, and a renewed appreciation for heart and brain health, cardio is once again front and center. However, it's not the same old “jog on the treadmill” cardio. It’s smarter, more individualized, and precisely programmed to meet all levels of goals, including weight loss, reducing visceral fat, longevity and improved healthspan, improving cholesterol, hormonal and metabolic health.

To help you better understand this what cardio program is best for your needs, Josh Berkovic, Dustin Millhollen and Kyle Reinstadtler, from DIAKADI’s team of advanced performance coaches, has compiled the latest research and insights on cardiovascular training—along with strategies for how to integrate it into your program based on your specific goals, whether that’s fat loss, longevity, heart health, or elite sport performance.

Follow the steps and advice below to dial in the exact cardio programming to meet your unique goals.

If at any time you would like one-on-one assistance from an expert, reach out to us directly using the button below, and a DIAKADI trainer can assist you with building your truly personalized cardio and strength program.

Need some help? Hire a DIAKADI trainer to develop your personalized program.

Step 1:
How to Calculate Your Zone 2 Heart Rate Range

Zone 2 is typically defined as 60–70% of your maximum heart rate (HRmax). This is the intensity where your body primarily uses fat as fuel, builds mitochondrial health, and allows for sustainable, low-stress cardio. Here's how to find your personal Zone 2 range:

Estimate your Max Heart Rate (HRmax) using the formula: 220 – your age
Multiply HRmax by 0.60 and 0.70 to find your Zone 2 range

🔢 Example (40-year-old):

HRmax = 220 – 40 = 180
Zone 2 = 60–70% of 180 = 108–126 bpm

You should be able to breathe through your nose and hold a conversation during Zone 2 work. Use a fitness tracker or smartwatch to monitor heart rate and stay within range.

Want a More Precise Method?

For those seeking accurate Zone 2 determination, consider lab-based or sport science testing. These methods assess your aerobic threshold (AeT) and determine exact heart rate zones:

Certified personal trainer Dustin Millhollen of DIAKADI Fitness taking a VO2 max test.

VO₂ Max Testing with Lactate Threshold Analysis: This lab-based test measures the maximum amount of oxygen your body can utilize during exercise. It’s typically performed on a treadmill or cycle ergometer while wearing a mask that captures and analyzes respiratory gases. Combined with lactate threshold testing—where small blood samples are taken during exercise to detect when lactate begins to accumulate—this test precisely identifies your aerobic threshold and ideal Zone 2 heart rate. For those of you in San Francisco, the most reliable testing site in the city is the UCSF Human Performance Center.
Gas Exchange Testing (e.g., INSCYD, PNOE): Measures oxygen and CO₂ to find your metabolic crossover point.
Field Testing Protocols: The MAF method (180 minus your age) or Zone 2 drift tests using a heart rate monitor and software like TrainingPeaks can offer close approximations.

If you’re working with a coach or training for high performance or longevity optimization, lab testing is well worth the investment.

How to Measure Your Cardio Fitness (Without a Lab)

Resting Heart Rate: A strong marker for overall cardiovascular health. Aim for <60 bpm.
Heart Rate Recovery: A drop of 20+ bpm within one minute post-exercise is ideal
The Talk Test: If you can speak comfortably in short sentences, you’re in Zone 2
VO2 Max Estimates: Use tools like the Bruce Protocol or 12-minute Cooper test as rough field tests.

Step 2:
What Cardio program matches your goals?

DIAKADI advanced-level personal trainers —Josh Berkovic, Dustin Millhollen, and Kyle Reinstadtler—agree on one major theme: the most effective cardio training is goal-specific. The science is clear: what works for sport performance may not be ideal for longevity. Here is a goal-by-goal breakdown based on their combined experience and research.

Goal	Recommended Cardio Approach	Specific Instructions	Notes, Supporting Research
Body Fat Reduction, Weight Loss	80% Cardio Workout Time = Zone 2 steady-state; 20% = 1–2 HIIT sessions per week to enhance EPOC (Excess Post-Exercise Oxygen consumption)	Bike, incline walk, stairclimb for 45–60 minutes 2–5 days/week in Zone 2, a pace where you can talk but not sing. Add 1–2 short 15-min HIIT sessions (rower, sprints) weekly.	Zone 2 burns fat efficiently ; HIIT boosts post-exercise burn
Visceral Fat Reduction	Moderate to high-intensity cardio (HIIT, MICT); 2–4x per week	Include 2 HIIT sessions (e.g., 30 sec hard/90 sec rest x 6 rounds) + 2 steady-state cardio sessions weekly. Track waist measurements over time.	High-intensity training is more effective for VAT reduction
Heart Health	3+ days/week Zone 2 (45–60 min); occasional intervals to increase cardiac output	Walk, cycle, or row in Zone 2 for 45 minutes 3–4x/week. Once/week, include short intervals (e.g., 3 min hard/2 min easy x 4) to strengthen your heart.	Cardio lowers LDL/triglycerides and raises HDL; Zone 2 supports eccentric cardiac hypertrophy
VO2 Max Improvement	Build base with Zone 2; progress to 4x4 interval model (4 min work, 3 min rest x4) at 90–95% HRmax	Start with 3 sessions/week of 45 min Zone 2 (see talk test). After 4–6 weeks, add 1 session/week of 4x4 intervals at hard effort (can talk only 1–2 words)	NTNU Norwegian 4x4 protocol highly effective
Metabolic Health	Emphasize Zone 2 for mitochondrial function; pair with resistance training and 1x weekly HIIT	Walk briskly for 45 min 4–5x/week; use resistance training 2–3x/week. Add 1 HIIT session weekly. Monitor glucose and energy levels for feedback	Improves insulin sensitivity and glucose control; All exercise boosts GLUT-4 expression
Cholesterol Management	Consistent moderate-intensity cardio (Zone 2); aim for 150 min/week minimum	Choose any enjoyable movement (brisk walk, hike, swim, cycle). Do 30–60 min per session, aiming for 5 days/week. Add variety to avoid boredom	Prolonged aerobic exercise > intensity to increase HDL; Aerobic exercise > resistance exercise to increase HDL
Longevity & Healthspan	Frequent low-to-moderate intensity (Zone 2), plus enjoyable movement for sustainability	Walk, ruck, hike, bike, or row at easy pace 5–6 days/week. Choose low-stress options that you enjoy. Mix in 1 session/week of intervals to maintain VO2 max	VO2 max is strong predictor of longevity; Low intensity cardio improves longevity

What cardio workouts to Avoid (and For Whom)

HIIT Without a Base: Jumping into high-intensity work without foundational aerobic fitness can lead to fatigue, poor recovery, and hormonal stress.
Over-Reliance on Any One Modality: A blend of Zone 2 and intervals is more sustainable than extreme specialization.
Ignoring Lifestyle Stress: For those with burnout or elevated cortisol, prioritize recovery-based Zone 2 and avoid excess intensity.

Final ThoughtS

Personal trainer Aurora Bellone doing Zone Two cardio on the step mill.

MAKE ZONE 2 WORKOUTS FUN + PRODUCTIVE: Zone 2 cardio are a staple part of the cardio program for nearly every fitness goal, but since it can eat up a good chunk of your week, it’s the perfect time to catch up on your favorite shows, podcasts, or even light work tasks (ie. email). To keep it engaging, I also recommend mixing in mini-circuits—like alternating standing pedaling, heavy resistance, and light resistance spin intervals—while still staying in your Zone 2 range. This way you build your aerobic base without the boredom.

START WHERE YOU ARE: As our coaches emphasized, consistency beats perfection. Whether you’re building a longevity-focused plan or prepping for performance, the right cardio mix depends on your body, your stress levels, and your goals. Start with what you enjoy, anchor it in evidence-based strategy, and build from there.

HIRE AN EXPERT AS NEEDED: If you’re unsure how to begin or want help refining your approach, reach out to our expert coaching team at DIAKADI using the button below. We’re here to help you develop a smart cardio program, for today and for the long haul.

Need help? Hire a DIAKADI trainer to develop a cardio program to meet your specific needs