My mother was diagnosed with heart failure in the middle of 2025 and the first thing I learned is that heart failure sounds a lot more dramatic than it actually is because what it really means is that her heart does not pump blood as efficiently as it used to and that is a gradual thing that happens to a lot of people as they age and it is managed with medications and lifestyle changes and it is not the sudden catastrophic event that the word failure makes you imagine. The number they track for it is NT-proBNP which goes up when the heart wall is stretched from working too hard and hers was stuck above 2100 for months and it stayed there through November of last year and then in April of this year it came down to 1200 and I have been trying to figure out what changed because the standard stuff was all still in place and she was already walking every day which she has done for years and she is seventy two so consistency matters more to her than intensity and I did not change her medications or her diet or anything her doctor had set up because that is not my place and I do not have the credentials for it. What I did was start her on Norwegian four by four in January after I had been reading the Wisløff study and the German Journal of Sports Medicine review and the meta-analyses that showed HIIT could improve VO2peak and cardiac function in patients with chronic heart failure and I figured that if the evidence was strong enough for people with reduced ejection fraction it was probably strong enough to try on someone who was just old and whose heart numbers were trending the wrong way. So multiple times a week I had her do four minutes on the stationary bike at a pace that pushed her breathing hard and then three minutes of easy pedaling and then another four minutes and another three and one more set and one more and the whole thing took about thirty minutes and she complained about it less than I expected because the intervals are short enough that the suffering feels contained and the recovery periods give you something to look forward to and she told me after a few weeks that she liked knowing exactly when the hard part would end which is the kind of thing you only appreciate when you are seventy two and your body has stopped pretending it has unlimited reserves.

I have no idea how much of that drop is actually from the exercise because this is not a controlled trial and there are a thousand variables I cannot account for and her doctors made adjustments I do not fully track and the body does its own mysterious things especially at that age where a good month of sleep and low stress can move biomarkers more than any intervention. What I can say is that the Norwegian four by four was the only thing I deliberately changed and the timing lines up and the mechanism makes sense because NT-proBNP is released when the heart wall is stretched from volume overload and exercise strengthens the heart muscle and improves its efficiency so the wall stretches less and the peptide levels drop and this is exactly what the literature describes even if SMARTEX-HF could not show a statistically significant advantage over moderate continuous training for the primary endpoint. I think about how in the Wisløff study the AIT group improved VO2peak from 13 to 19 ml/kg/min while the moderate continuous group barely moved and how the meta-regression by Uddin showed that every ten percent increase in training intensity was associated with an extra 1 ml/kg/min in VO2peak and how the German review concluded that HIIT is an equivalent form of exercise for CHF patients that produces similar improvements in cardiovascular protection factors and quality of life. The evidence is not screaming at you but it is pointing in a direction and that direction is that pushing harder in short bursts does something that steady walking does not do and I think that something is probably what brought my mother’s number down.

I have completely switched my own exercise to Norwegian four by four now even though I do not need it for the same reasons and I do it three times a week and the intervals are brutal in a way that running at a steady pace never was because the fourth interval is always a negotiation with yourself about whether you can hold the intensity for sixty more seconds and you always can and that negotiation itself is probably part of why it works because the cardiovascular system adapts to peak demands not to average demands and if you never ask it for a peak it never learns how to deliver one. My mother still walks every day because she loves it and that is more important than the exact protocol and the walks give her the baseline movement that keeps her joints mobile and her mood stable and the intervals give her heart the stress it needs to stay strong and the combination of both is probably better than either alone and that is the thing about exercise that the literature sometimes misses which is that the best protocol is the one the person actually does. If she hated the intervals we would have stopped and if she did not have her walks she would be sedentary and neither extreme is useful and the evidence has to meet the person where they are.

Try this with someone you love and tell me how it goes. I am @troysk704.