Comedian Joanne McNally has found a fitness approach that fits her busy schedule: sprint intervals that take just 20 minutes but deliver results that last all day.
The Celebrity Traitors star recently shared her no-nonsense approach to running on her podcast My Therapist Ghosted Me, revealing she’d invested in Nike Vaporflys—those fluorescent running shoes with carbon plates that serious athletes swear by.
But what makes her training routine particularly interesting isn’t the fancy footwear.
It’s the brutally efficient sprint protocol she follows—and the science-backed benefits that come with it.
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McNally’s 20-Minute Treadmill Protocol
McNally’s approach to interval training is refreshingly straightforward, as she explained to The Irish Times.
I sprint, but I don’t actually go anywhere. It’s interval training. I turn the treadmill on high and leg it as fast as I can for 60 seconds, then hop off for 60 seconds, back on for 60, off for 60. I do this for 20 minutes.
She credits a trainer with teaching her the metabolic benefits of this approach, though she admits her consistency could use work.
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A trainer told me it turns your body into a fat-burning incinerator for the entire day. It will just cremate whatever you put into it, like a piggish steam engine.
Her self-aware humor about workout adherence resonates with many who struggle to maintain consistent routines.
Naturally, I will do my sprints on a Monday and assume that this means my body will continue to burn fat at this supersonic speed for the rest of my life.
Why Indoor Sprinting Works Better for Some
McNally prefers the controlled environment of treadmill training for practical—and hilarious—reasons.
I have tried to do it outdoors but all the stopping and starting looks strange. I look like I’ve just heard a family member is gravely ill, but I keep changing my mind about how much I care.
Beyond the comedic value, treadmill sprinting offers genuine advantages: consistent pacing, precise timing, and weather independence.
The controlled environment eliminates variables that can interfere with outdoor interval work, making it easier to track progress and maintain intensity.
The Science Behind Sprint Intervals
Rebecca Bossick, co-founder and clinical director at One Body LDN, explains why McNally’s approach delivers such impressive results.
Research shows that just one minute of all-out sprinting, three times weekly, can improve aerobic fitness by 19% and enhance insulin sensitivity within 12 weeks.
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That efficiency rivals what you’d achieve from 50 minutes of moderate exercise per session—a remarkable return on time investment.
Metabolic Benefits That Last
Sprint intervals create an “afterburn effect” technically known as excess post-exercise oxygen consumption (EPOC).
Your metabolism remains elevated for hours after finishing, continuing to burn calories at an accelerated rate.
This becomes particularly valuable during perimenopause and beyond, when hormonal changes can make blood sugar regulation more challenging and metabolism naturally slows.
Preserving Fast-Twitch Muscle Fibers
Sprinting trains Type II muscle fibers—the ones responsible for quick, powerful movements.
Bossick emphasizes their importance: “These are the fibres that shrink the most as we get older. For women, this loss of muscle and power tends to accelerate around menopause as oestrogen levels fall, so training these fibres in your 40s is one way to hold on to them for longer.”
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Maintaining these fibers means preserving functional strength—the kind needed for carrying groceries, climbing stairs, or catching yourself if you trip.
Building Stronger Bones Through Impact
Each sprint creates a forceful push against the ground, loading bones in ways that stimulate density improvements.
Studies of master sprinters in their early 70s revealed 10% higher hip bone mineral density compared to endurance runners and 14% higher density than sedentary adults.
Bossick notes that combining strength training with sprint intervals at least twice weekly helps maintain bone density—critical protection against osteoporosis risk that increases after menopause.
Getting Started: Hill Sprint Protocol
Bossick recommends hill sprints for beginners because the incline naturally limits speed and reduces hamstring injury risk.
Find a moderate incline where you can run 40-60 meters continuously.
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Warm-Up Phase
- Five minutes easy jogging
- Five minutes dynamic stretching: leg swings, high knees, heel flicks
- Three gentle practice runs at the hill’s base
Main Session
Complete six rounds of 10-15 second sprints at 85-90% maximum effort.
Walk slowly downhill for recovery, taking 90 seconds to two minutes between efforts.
Add one or two sprints weekly until reaching 10 total rounds.
Bossick advises: “Lean slightly forwards from your ankles, pump your arms and take short, quick steps, landing with your feet underneath your hips rather than reaching out in front.”
Cool-Down
- Five minutes walking
- Stretching for calves, hamstrings, hip flexors
Treadmill Sprint Alternative
For those who prefer McNally’s indoor approach, Bossick offers a progressive treadmill protocol.
Warm-Up
Walk five minutes, gradually building to a light jog at 1% incline.
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Initial Protocol
Eight rounds of 30 seconds hard running followed by 90 seconds walking recovery.
Progression Path
- Intermediate: 45 seconds on, 75 seconds walking
- Advanced: 60 seconds on, 60 seconds off (matching McNally’s protocol)
Bossick cautions: “Remember that treadmills take a few seconds to speed up and slow down, so start your timer when the belt reaches your target speed.”
Maintain tall posture with eyes forward, staying centered on the belt rather than drifting toward the front.
Cool-Down
- Five minutes easy walking
- Gentle stretching
McNally’s Broader Fitness Journey
Sprint intervals represent just one component of McNally’s evolving approach to wellness.
During lockdown, she tracked daily steps on a Fitbit while walking around Dalkey, according to the Irish Examiner.
More recently, she discovered reformer Pilates—a complement to her high-intensity sprint work.
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After one 60-minute class, I have entered my Pilates era. I’ve caught the wellness bug. If I start journalling, please call my mum.
This combination of high-intensity intervals and low-impact strength work creates balanced training that addresses cardiovascular fitness, power, and mobility simultaneously.
Practical Tips for Sustainable Sprint Training
Bossick recommends limiting sprint sessions to one or two per week initially, with at least one rest day between efforts.
This recovery period allows your body to adapt without overwhelming your system—crucial for injury prevention.
Sprint training places significant demands on muscles, tendons, and connective tissue unaccustomed to explosive movements.
Key Safety Considerations
- Never skip warm-ups: Cold muscles are injury-prone muscles
- Progress gradually: Adding too many intervals too quickly invites overuse injuries
- Listen to sharp pain: Muscle fatigue is normal; acute pain is not
- Prioritize form over speed: Proper mechanics prevent compensation patterns that lead to injury
Maximizing Long-Term Benefits
The NHS classifies hill sprints and interval running as “very vigorous” activities—appropriate intensity for significant fitness improvements.
Consistency matters more than perfection.
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Two quality sprint sessions weekly deliver better results than sporadic heroic efforts followed by weeks of inactivity.
McNally’s humorous acknowledgment of her inconsistent adherence highlights a universal challenge—but even irregular sprint training provides benefits that steady-state cardio cannot match.
Why Time-Efficient Training Matters Now
For women juggling careers, families, and personal commitments, McNally’s 20-minute protocol offers realistic fitness integration.
The disproportionate benefits of short, intense efforts make sprint intervals particularly valuable during life stages when time becomes the limiting factor.
You don’t need hours at the gym to build meaningful fitness.
Twenty minutes of focused sprint work delivers cardiovascular improvements, metabolic enhancement, muscle preservation, and bone strengthening—a comprehensive fitness package in less time than most streaming episodes.
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McNally’s approach proves that effective training doesn’t require elaborate programming or expensive equipment beyond a good pair of running shoes and access to either a treadmill or a hill.
The barriers to entry are low, the time commitment is manageable, and the results speak for themselves.
