Quick answer: Yes, if it is short, genuinely hard, and placed well. The Phaes HIIT session is 20 minutes of 40 seconds work and 20 seconds rest, rotating jumping and bodyweight moves such as squat jumps, lateral hops, mountain climbers, and push-ups. It adds impact for bone and power for muscle. Keep it off the day before your sprint session, and swap jumps for low-impact versions if your joints or pelvic floor need it.
HIIT has a mixed reputation for women over 40. Some say it is the fastest way to get fit; others say it spikes stress and wrecks recovery. Both are partly right, and the difference is the dose. Short, hard, well-placed HIIT helps. Long daily classes on top of poor sleep do not. Here is the session Phaes uses and how to fit it in.
Is HIIT good for women over 40?
Yes, when it is short, genuinely hard, and has room around it to recover. A 20 minute circuit of jumps and bodyweight moves adds power, impact for bone, and fitness in very little time. What goes wrong is volume: daily 45 minute classes stacked on broken sleep and heavy lifting leave nothing in the tank for the sessions that build muscle.
Two things change after 40. Muscle power, the ability to produce force quickly, declines faster than strength with age, and jumping is one of the most direct ways to train it. And bone needs impact as well as load. UK consensus guidance on exercise and osteoporosis, Strong, Steady and Straight (Brooke-Wavell and colleagues, British Journal of Sports Medicine, 2022), recommends impact exercise alongside muscle strengthening for bone health. Jumps deliver both.
The Phaes HIIT format
The Phaes HIIT session is 20 minutes of 40 seconds work and 20 seconds rest, which is 20 rounds. Each round is one move from a set of eight: lateral hops, box jumps, skipping, depth jump to jump, mountain climbers, push-ups, single-leg jumps, and squat jumps. Work hard in every 40 seconds and use the 20 seconds to reset.
This is different from the sprint interval session, which is a handful of all-out running or bike sprints with 90 seconds of easy recovery. SIT is the main quality session of the week. HIIT is a short circuit that adds impact and power. Phaes coach Kristina Folcik keeps them as separate sessions with separate jobs, rather than one long hard day.
Warm up for about 5 minutes first: easy marching, leg swings, a few bodyweight squats, and some gentle hops to wake up your feet and calves.
- Warm-up 5 min easy marching, leg swings, squats Z1
- Main set 20 min: 20 rounds of 40 s work, 20 s rest, rotating 8 moves Hard
Not the day before your sprint session, and not in a reset week.
A written 20-minute session
Here is a full session using all eight moves. Run through the list twice, then finish with the first four once more. Every round is 40 seconds of work and 20 seconds of rest, and the whole thing takes exactly 20 minutes after your warm-up. Quality beats speed: stop a move early if your form breaks down.
| Rounds | Move | Cue |
|---|---|---|
| 1, 9, 17 | Squat jumps | Sit back, jump tall, land soft and quiet |
| 2, 10, 18 | Lateral hops | Side to side over a line, light and quick |
| 3, 11, 19 | Mountain climbers | Hands under shoulders, hips level |
| 4, 12, 20 | Box jumps | Low box, step down rather than jumping down |
| 5, 13 | Skipping | Rope or no rope, stay on the balls of your feet |
| 6, 14 | Push-ups | Floor or hands on a bench, body in one line |
| 7, 15 | Single-leg jumps | Small hops, switch legs halfway |
| 8, 16 | Depth jump to jump | Step off a low box, land, jump straight up |
A few notes:
- Box height: start with an aerobics step or a low box. Height adds risk faster than it adds benefit.
- Depth jumps: step off, do not jump off. The skill is a quick, quiet landing followed by an immediate jump.
- Push-ups: any version you can do well counts. Hands on a bench is a full push-up, not a lesser one.
Swaps for joints and the pelvic floor
Every move has a lower-impact version that keeps the 40/20 structure. Use the swaps if your knees, hips, Achilles, or pelvic floor are not ready for jumping, or on a day when symptoms flare. Then add impact back one move at a time, over weeks, as long as it feels fine during the session and the next day.
| Move | Lower-impact swap |
|---|---|
| Squat jumps | Bodyweight squat to a heel raise |
| Lateral hops | Lateral shuffle or step-touch |
| Box jumps | Fast step-ups onto the box |
| Skipping | High-knee march |
| Depth jump to jump | Step down, pause, then squat to a heel raise |
| Mountain climbers | Slow climbers with hands on a bench |
| Push-ups | Incline push-ups against a bench or wall |
| Single-leg jumps | Single-leg calf raises |
Leaking, heaviness, or a dragging feeling during jumps are common in perimenopause and are worth taking seriously, not just pushing through. A pelvic health physiotherapist can assess you. Our page on the pelvic floor in perimenopause explains why it changes and what helps. Joint pain that lingers into the next day is a sign to stay with the swaps longer.
How HIIT fits with sprints and lifting
HIIT works best as one or two short sessions a week, kept away from your sprint day. Never put it the day before SIT, because tired legs mean slower sprints. A good slot is two or three days after SIT, on a day you lift upper body or have an easy run. In reset weeks, every fourth week, HIIT comes out completely.
A sample week with all three:
- Monday: lift (upper body) and easy walk
- Tuesday: SIT inside a short run
- Wednesday: lift (lower body)
- Thursday: easy run or yoga
- Friday: HIIT, 20 minutes, plus a short upper-body lift
- Saturday: long easy run or walk
- Sunday: full rest
That week has three hard things in it: sprints, heavy lifting, and HIIT. Every other session is easy, and one day is fully off. If a bad night lands before a hard day, the HIIT session is the first one to swap for a walk. For the lifting side, see how often women over 40 should lift.
When to skip it
Skip HIIT, or switch it for a walk, after a bad night, during a symptom flare, when you are ill, or when an injury hurts with impact. It is the most flexible session in the week, so it should be the first thing you drop when recovery is short. Get medical advice before hard exercise if you have chest pain, palpitations, dizziness, or a known heart condition.
Signs that HIIT is too much for you right now:
- Sleep gets worse on HIIT days.
- Soreness lasts more than two days.
- Your sprint session or heavy lifts are getting worse, not better.
- You dread it every week.
Any of those means less, not more: shorten the session, use the swaps, or drop it for a few weeks while the rest of the plan does the work.
Where Phaes fits
Phaes uses the 40/20 HIIT session in the quality slots that are not your sprint session, keeps it off the day before SIT, rotates the moves, and offers low-impact swaps when your joints or pelvic floor need them. It reads your cycle, symptoms, and daily check-in, and on a rough day it turns HIIT into an easy session instead of asking you to grind through it.
The bottom line
HIIT is good for women over 40 when it is short, hard, and well placed: 20 minutes of 40 seconds on and 20 off, using jumps and bodyweight moves, once or twice a week, never the day before sprints, and never in a reset week. Use lower-impact swaps when you need them, and let sleep and symptoms decide when to skip it.
Frequently asked questions
Is HIIT bad for women in perimenopause?
No, but too much of it can be. One short, hard session a week fits well alongside heavy lifting and one sprint session. Problems usually come from stacking long, daily HIIT classes on top of poor sleep, which leaves no room to recover. Short and well placed is the version that helps.
How long should a HIIT workout be over 40?
Twenty minutes of work is enough, plus a few minutes of warm-up. The Phaes session is 20 rounds of 40 seconds on and 20 seconds off. Longer sessions tend to drift into a moderate pace that is tiring without being hard enough to build power, which defeats the point of interval work.
Is HIIT the same as sprint interval training?
No. Sprint interval training is a few all-out efforts of 20 to 30 seconds with 90 seconds of easy recovery, usually done running or on a bike. HIIT, as Phaes uses it, is a continuous 20 minute circuit of 40 seconds work and 20 seconds rest using jumps and bodyweight moves. They do different jobs, so keep them on different days.
Can I do HIIT with pelvic floor problems?
Often yes, with low-impact swaps. Replace jumps with step-ups, marching, and squats to a heel raise, and add impact back gradually as symptoms allow. Leaking, heaviness, or pain are signs to scale back and see a pelvic health physiotherapist, who can tailor a plan to you.
How often should I do HIIT after 40?
One or two short sessions a week is plenty for most women who also lift heavy and do one sprint session. More is not better if it eats into recovery for the sessions that matter most. Skip HIIT entirely in your reset week, every fourth week, when all intensity comes out.
Does HIIT help bone density?
The jumping parts can. UK consensus guidance on exercise for bone recommends impact work, such as jumps and hops, alongside strength training. A HIIT circuit built on jumps adds that impact in a short session. It does not replace heavy lifting, which loads bone through muscle pull.