Once you hit your 30s, building muscle takes more than just showing up to the gym a few times a week. Hormones shift, careers and families demand more time, and the training and recovery methods that worked in your 20s don’t always cut it anymore.

If you're training consistently but not seeing the gains you want - you're not alone.

Here are 6 of the most common reasons people in their 30s and 40s struggle to build muscle (and what to do about it):

1. You’re Not Lifting Heavy Enough (or with Enough Effort)

Muscle growth doesn’t come from going through the motions - it comes from giving your muscles a reason to adapt.

The truth is, most people stop a few reps into the burn - but that’s not muscular failure. It just feels uncomfortable. In reality, most of us have 3–5+ more reps left than we realise. That effort gap is often the difference between maintaining and actually building muscle.

Fix it: Aim to take at least 5 hard sets per muscle group per week to true failure (where you physically can’t complete another rep with good form), and keep the rest of your working sets within 3 reps of failure.

Train mostly in the 6–20 rep range, which offers the best balance of load, volume and joint-friendliness for muscle growth.

2. You’re Not Eating Enough to Grow

Muscle isn’t built from training alone - you need the raw materials too. And that means eating in a calorie surplus, not a deficit.

Many people in their 30s and 40s unintentionally under-eat, often because they’re trying to minimise fat gain. Add in the time pressures of work and family, and the problem worsens - they default to healthy but lower-calorie convenience foods, or match the portion sizes of their kids without realising.

And if they don't under-eat overall, they often under-eat crucial building blocks like protein.

Over time, this leads to chronically low energy intake and stalled progress.

Fix it: Aim to eat 2–300 calories above your maintenance each day to support muscle growth. Protein should be set at around 1.5–2g per kg of your target body weight to give your muscles the building blocks they need to grow. Don’t fear food - it’s fuel.

3. Lack of Recovery and Sleep

Another common reason people struggle to build muscle in their 30s and 40s is the lack of proper recovery, especially sleep.

Sleep is essential for muscle growth and overall recovery. When we sleep, our bodies repair, rebuild, and grow muscle tissue. But as we get older, many people find themselves struggling to get enough restful sleep due to family, work, or other commitments.

I know that 8 hours can feel unrealistic - especially with kids, work deadlines, or late nights socialising. But if 6–7 hours is more realistic, then at least make those hours high-quality. Focus on sleep hygiene to ensure those few hours count. Here’s how:

Go to bed and wake up at the same time each day (even on weekends)
Make your room cool, dark, and quiet - blackout curtains or an eye mask can work wonders
Limit screen time before bed and avoid bright lights (blue light from phones and devices interferes with melatonin)
Cut out caffeine in the late afternoon and evening to prevent it from disrupting your sleep quality

In addition to sleep, active recovery (like stretching, foam rolling, or even yoga) plays a significant role in reducing soreness and preventing injuries. Rest days are crucial, but so is ensuring you’re giving your muscles the right environment to grow.

4. Your Training Plan Isn’t Structured for Growth

Building muscle requires a structured approach with a focus on progressive overload. If you’re constantly jumping from machine to machine or changing exercises too often, you’re missing out on the key to muscle growth: sticking with a consistent plan.

To build muscle, you need to gradually increase the demands you place on your muscles. A simple and effective method is the double progression scheme. This means you focus on two things:

Increasing the number of reps you can do with the same weight
Increasing the weight once you’ve hit the upper end of your rep range

Example of Double Progression:

Let’s say you’re doing squats with 60kg for 3 sets in the 8-10 rep range. Here’s how double progression works:

Week 1: You do 3 sets of 8 reps with 40kg
Week 2: You do 3 sets of 9 reps with 40kg
Week 3: You do 3 sets of 10 reps with 40kg (now you’ve reached the upper end of your rep range)
Week 4: Increase the weight to 62.5kg and start again at 8 reps

The goal is to gradually increase either reps or weight over time, which ensures that you're progressively challenging your muscles and giving them the stimulus they need to grow.

Consistency is key. To see real progress, aim to follow the same training plan for 8-12 weeks. This allows your muscles to adapt and grow without being distracted by constantly changing exercises or routines. Stick to your plan, focus on progressive overload, and you'll see better results.

5. You’re Following the Same Workout Structure as When You Were 19

As we age, our training needs change, but many of us continue following the same workout structure we used in our teens and early 20s. If you’ve been sticking with a body part split (chest day, back day, leg day), it might be time for a change. These routines were designed for bodybuilders with plenty of recovery time and minimal concern about injury. But they aren’t always the best for building muscle or staying injury-free as we age.

Instead of isolating muscle groups, full-body workouts or an upper-lower split are more effective. These approaches allow for more frequent muscle group engagement, better recovery, and sustainable strength gains.

Full Body Workouts

If you’re training 2-3 days per week, full-body workouts are ideal. They target all your major muscle groups in one session, helping you keep volume and frequency high while ensuring no muscle group is left behind.

Upper/Lower Split

For those who train 4 days a week, an upper-lower split offers great balance. This method lets you hit each muscle group twice a week, giving you enough recovery time and allowing for balanced growth and strength development.

As you age, it’s important to adapt your training plan. The body part split may no longer be the most efficient or sustainable way to build muscle in your 30s and 40s. Instead, full-body workouts or an upper-lower split provide better frequency, muscle engagement, and recovery - all key factors in staying strong and injury-free as you get older.

6. You’re Missing Power, Mobility, and Pure Strength Work

As you get older, focusing on muscle and strength alone isn’t enough to maintain long-term health and injury prevention. Incorporating power training, mobility, and a few pure strength sets into your routine is essential for preserving overall movement quality and avoiding injury, thus, ensuring you can consistently push hard toward your muscle building progress.

Why These Matter:

Power Training: Incorporating explosive movements (like kettlebell swings, medicine ball throws, or jumps) helps maintain power, which naturally declines with age. Power is essential for preventing falls and keeping functional strength for daily life.
Mobility Training: Keeping your joints mobile and robust reduces the risk of stiffness, discomfort, and injury. Alongside sensible resistance training through a full range of motion, adding dynamic stretches, yoga, or direct mobility drills helps you feel better and move more efficiently.
Pure Strength Sets: While hypertrophy (muscle-building) is important, pure strength work (e.g., heavy squats, deadlifts, lunges, presses, and rows in the 3–5 rep range) ensures that you maintain maximal strength. This helps with hypertrophy, posture, joint integrity, and overall body resilience.

Power, mobility, and strength work aren’t just for athletes - they're vital for anyone looking to stay strong and healthy through their 30s and into midlife. By adding these elements to your routine, you’ll not only avoid injury but also build a more muscular, resilient, capable body that can perform well in everyday life.

Are you ready to future-proof your health and build the strength you need to glide through life? Start today, and let’s work together to ensure your best years are ahead of you.

Work with me

And as always, feel free to drop me a message if you have any questions.

6 Common Reasons People in Their 30s & 40s Struggle to Build Muscle (And What to Do Instead)