In a world where we sit more than we move, our bodies are quietly adapting — and not in our favor.

Last week, I wrote aboutpostureand how it’s deeply tied to core strength and shoulder mechanics. One of the biggest reasons posture has become such a widespread issue is simply that our lives revolve around sitting — cars, computers, meetings, meals.

This past week, I worked with a client who travels internationally for work. He sits 10–20 hours on flights, then sits again in meetings, conferences, and dinners — only to fly home and do it all over again. Even though he makes time for 30–45 minutes of daily exercise, it can’t fully offset the hours spent with his hips and knees locked at 90 degrees and his spine flexed forward.

When he asked why he feels so stiff and tight, I had to explain something many people don’t realize:tightness isn’t caused by a lack of stretching — it’s caused by muscle weakness.

In this week’s newsletter, we’ll look at eight common signs that you may be living a sedentary lifestyle, how to reverse it through muscle activation, and why flexibility alone won’t improve your mobility. You’ll also find a free workout and educational video to help you start moving with purpose.

Table of Contents

🔬Science Spotlight: 8 Signs You’re Sitting Too Much — and How to Fix It
💪Sedentary Tightness: Why stretching alone doesn’t improve flexibility.
🎥Free Video: "Mobility Reset: Lower Body" Workout on FIS OnDemand

Science Spotlight

🪑 8 Signs You’re Sitting Too Much — and How to Fix It

If you spend most of your day sitting — whether at your desk, in the car, or on the couch — you’re not alone. Studies show that one in four adults doesn’t meet basic activity recommendations, and that long stretches of sitting are now being linked to nearly every major chronic condition, from cardiovascular disease to muscle atrophy.

The truth is, your body was designed to move. Muscles are meant to contract, adjust, and stabilize joints — not remain idle for hours. When they don’t, the entire system begins to weaken. Here areeight common signs you might be leading a sedentary lifestyle, plus how to start reversing the effects using my 5-Step Cycle of Muscle Maintenance.

1️⃣You’re Not Meeting Basic Exercise Guidelines

If you’re not getting at least 150 minutes of moderate activity per week, or two days of resistance training, you may already be losing strength and mobility. Research shows muscle decline can begin within just two weeks of inactivity.

Start small.Begin with gentle activation work like isometric contractions (Step 1: Isolate) to wake up muscles safely before progressing into more dynamic movement. Remember — consistency always wins over intensity.

2️⃣You Sit for Most of the Day

When you spend more than half your waking hours sitting, muscle activity drops to near zero, circulation slows, and joint stiffness sets in.

Try this:Set a reminder to get up every hour for 3–6 minutes. Walk around, do sit-to-stands, or try a few isometric contractions — small actions make a huge difference.

3️⃣ You Feel Tired All the Time

It sounds backward, but the less you move, the more fatigued you become. Inactivity deconditions your heart, lungs, and muscles — leaving you drained.

Solution:Low-intensity movement, such as walking or light resistance training, can actually boost your energy by up to 20%.

4️⃣You’ve Gained Weight or Your Metabolism Feels “Sluggish”

When you sit too long, your calorie burn plummets. The result? Stored fat, higher blood sugar, and lower insulin sensitivity.

Try moving more before cutting calories.Incorporate resistance training 2–3 times a week. Even simple band or dumbbell workouts increase lean muscle, which drives up your metabolism and supports healthy glucose regulation.

5️⃣You’re Winded After Light Activity

When we sit too long, our hearts and lungs adapt — but in the wrong direction. The heart pumps less efficiently, and shallow breathing limits oxygen supply.

Start where you are.Reintroduce cardiovascular activity slowly. Try alternating short walking intervals with resistance-based work to build endurance while maintaining muscle integrity.

6️⃣You’re Not Sleeping Well

People who sit more than 11 hours a day are more likely to experience insomnia and restless sleep. Movement helps regulate hormones like melatonin and cortisol, improving both sleep quantity and quality.

Try this:Gentle evening movement — like Integrated Isometrics or breathing-based stability work — helps regulate cortisol and prepare your body for deeper, more restorative rest.

7️⃣Your Mood and Focus Have Declined

Your brain, like your muscles, thrives on blood flow. Long hours of sitting reduce circulation to key memory centers, including the hippocampus. The fix? Movement.

Mindful Movement.Bring awareness to your body as you move. Exercise that connects breath, posture, and control — such as the integrated strength practices in FIS OnDemand — strengthens both body and mind.

8️⃣You’re Becoming More Forgetful

Long hours of sitting are linked to reduced thickness in the brain’s memory centers. The good news? Regular aerobic activity and strength training can reverse this trend.

Keep the brain active through the body.Regular strength training enhances brain function and slows cognitive decline.

🧬 What Happens When You Sit Too Long

When you remain still,mechanoreceptors— the sensory cells that detect pressure and motion — stop firing. This lowers neuromuscular communication, reduces joint lubrication, and suppresses the natural pump of lymph and blood through the body. Over time, these small changes add up to stiffness, pain, and premature muscle inhibition.

The good news: every time you contract a muscle, you reactivate those receptors, rebuild neuromuscular pathways, and remind your brain how to support healthy movement.

Reference 📚
Frazier, R., Cherian, V., et. al. (2024, March 25).Do You Have a Sedentary Lifestyle?Real Simple. From:https://www.realsimple.com/health/fitness-exercise/sedentary-lifestyle-signs

Free FIS On Demand Video

Why Flexibility Exercises Won’t Improve Your Mobility

Confused about the difference between mobility vs. flexibility? Or why your flexibility stretches aren’t delivering the results you hoped for? In this video, I’m breaking down the science and giving you three exercises you can do that WILL help you feel better.

You’ll learn:

✔️ Why stretching alone doesn’t improve flexibility.

✔️ The key to better mobility (hint: it’s about muscle contractions).

✔️ Three exercises to improve control in your hips, back, and hamstrings.

Discover how to move better, reduce pain, and create lasting results with a smarter approach to training.Watch it Now

FIS On Demand Lower Body Reset

Tightness is often a sign that muscles are weak. In this workout, we will improve mobility of the lower body using the FIS 5-Step Cycle using bodyweight and dumbbells to strengthen weak muscles.

We’ll begin with isolated hip activations, integrate them into multi-joint holds, then move into dynamic transitions. As we add load, you’ll feel how seamlessly your movement improves. The session ends with a powerful challenge to optimize muscle health and function.

➡️Watch now on FIS On Demand

Join FIS OnDemand

💭Final Thought

This week, let’s get moving — even if it’s only a few minutes at a time. Every muscle contraction is a message to your body that you’re alive, strong, and capable of change.

Your muscles are waiting for you.

Cheering you on!💙

Lauren Eirk
Founder, Fitness Integrated Science