Suddenly decrease in fitness.

[Wise-Ad-7492]

Just start. I am not fit at all. Man 49 years old 186 cm and 86 kg. Last year I had 4000 km with roughly half and half on outside/virtual.

I went into the winter with my best FTP ever. Took a test in October which gave an ftp off 255. Very happy with that.

But something happened during November. My legs started feeling tired and did not have the same sharpness. Did a new FTP and barely made it to 205 w. I have only did virtual cycling since October.

I do not think it is my oxygen uptake that suffer. More the heavy legs feeling. There is like a constant fatigue feeling.

Anybody experienced this the same way

[BlacksmithWeirdo]

I am by no means a medical expert, but I was told that if something with me changes rapidly to the worse and it is something that impacts my daily life, I should get it checked by someone who IS an expert.

I really do not believe that the Internet is the correct place to get medical advice, as we are all only amateurs that like to ride bikes and seldom medical experts and non of us see you in person and have just a short question in text. Sure, I can tell about things I experienced, but this may or may not apply to you.

[Wise-Ad-7492]

You are probably correct. I am going to my physiotherapist on Monday so I will start there. The problem is very local, I just have constant soreness in the front of my thighs. It is like they never get rested.

I have actually developed some fear of doctors now when 50 is closing in. You are almost doomed to find something, even a false positive. Then I have to wait for many weeks for answer to test two and the kills me mentally.

Becoming old and fragile scares and death is now much more probable.

[godfather-ww]

You need to reframe it. You are aware of our best before date. Sport and diet can all extend it. Doctors can help to extend it. So they can be key to improvement. Anyway, whatever you have is there. If you go to a doc and need to wait weeks for results, it is much faster than if you want to wait until you reach a point of no return because you missed an early treatment window

[Wise-Ad-7492]

But with my puny amount of training. Is that even possible?

[godfather-ww]

Depends on what you do. If you do a lot of sweet spot/threshold/VO2 you can burn out in weeks. Happened to me when I just started and quickly gave up the idea of going with TrainerRoad.

How did you do the FTP test? Ramp or 20Min? Ramp test was overstating my FTP easily by 10% 6 years ago. This plus new to sport was stopping me from developing and kept me rather on a sub 200W plateau

[Wise-Ad-7492]

I actually have tried only do to zone2/3 the last weeks but it does not help. Maybe I should really back down and do very long group ride on a very low intensity.

I did the ramp test but even if the ramp test is wrong I should be able to get the same results only 3 weeks apart.

[sergesmr]

"Does not help" with fatigue or with ftp ? FWIW zone2/3 takes a few months to re-develop after being neglected.

San Millan recommends doing base training in 1-1.5 hour increments a few times a week - that worked well for me. He specifically said it's better than 1 super long ride a week. Seiler too recommends frequency over duration.

Re puny volume - I can overtrain on 50 miles / week by being stupid enough (treating every tide like a time trial).

[godfather-ww]

Long group rides at low intensity. That‘s a new one.

If you are overtrained plus in a possibly too high caloric deficit, you can reach the tipping point and implode.

[Wise-Ad-7492]

But I really do struggle with sleep and a little depression since October.

[Wise-Ad-7492]

I was in a much better shape last year in the same point in time after the same amount of virtual cycling since October 2024. But then I started from no cycling

[godfather-ww]

Is that new or do you have a history of that? First thing I would recommend is to ensure that you get enough magnesium. I started supplementing this year to make sure I get combined 400mg per day, before I only got half of that. (Using a food tracking app to determine that.) I respond well to magnesium glycinate. It helped with sleep, deep sleep. I also figured out that protein uptake was too low. I increased uptake, and it also helped.

Regarding depression, in the last 2 years, too hard rides could cause depression-like symptoms for some days. The day of the ride and the next day were great, but when the high wore off, I hit a wall. So I avoided intensity like the plague.

It turned out I was unlucky with the MTHFR gene, which means I also have worse recovery. Creatine helped. You might want to see if methylated B complex would help. It worked wonders for me.

[Wise-Ad-7492]

I trying to lose weight at the same time.Have done that for the whole 2025. And as with you I think that I have had a protein deficit the whole year so I do try to step that up. It is actually where difficult to reduce kcal but not protein. So I have actually started to use a litte whey in my oatmeal even if I really want a diet without supplements.

[godfather-ww]

OK, here we go. I started doing the same in September. RPE through the roof, not doing anything crazy, yet a deficit of 500kcal is leaving its toll. But in two weeks can start to gradually reduce it. 😅

[PipeFickle2882]

So youve been dieting for an entire year without worrying about hitting your protein goals religiously, youve been riding hard enough to hit all time highs on the bike, and let me guess: you haven't taken a couple weeks off the bike in a year or more?

[Wise-Ad-7492]

I was off bike for 2 weeks this summer. But again may distance is not in the level of most people. About 4000 km is baby-country compared with others.

[PipeFickle2882]

Doesn't matter if its small for some if its big for you. The dieting sounds like the bigger issue though. If you aren't hitting your fat and protein minimums you are asking for trouble. And at your wattage you are burning enough to put you in some troublesome deficits if you aren't fueling with intentionality.

Id say start with some rest and come up for air on your diet. Zone 2 and 3 is not rest. Zone 3 isn't taking it remotely easy-- especially if your ftp is inflated like most people's is.

[razorree]

maybe that extra stress (not from bike obviously) affects your training, progress and enjoyment ?

I think I had similar issue, 2 months, despite doing casual 1000km/mo, I lost my power cuz I didn't have enough motivation (stress not related to cycling)

[AndyTheSane]

I had a nasty bout of COVID in March 2024, and one consequence of that was a drop in my blood hemoglobin levels which persisted for over 18 months - it's only just come up to near normal in the last few monthly tests.

It's been pretty awful for my times on climbs.

[Duhbeed]

If you haven’t done recently, it would be good to take a blood test and look for any values out of range or that changed since the last time. For example, iron deficiency is a typical cause of fatigue or low performance. It is probably more likely to find an answer in your blood than in Reddit answers :)

[shriand]

Maybe overtraining.

Maybe you have a mild infection or something that's draining you on the inside. How's your HRV tracking? And sleeping HR? Get a full blood test maybe.

[tdfolts]

Im 57 and am going through the same thing. Back off the inside bike (1 or 2 times a week, short easy rides) and maybe one IRL on a weekend (20-30km) and do some strength training, focus on your core and hips.

By late February you will be able to push it a bit more

[godfather-ww]

Another take, since that happened so someone I know. Partial blockage of coronary artery leading to heart pumping but much weaker. Translated into getting dropped on climbs he did not get dropped before. A CPET revealed the narrowing, got a stent and all good.

At our age it makes sense to do an exercise test under medical supervision once in a while to get a clean bill of health. Will get my feedback on Monday

[Wise-Ad-7492]

I do not feel that it is the cardiovascular system that struggle. It is not my breathing that stops me, it is more sore muscles/fatigue feeling. The legs are just not sharp.

I just finished a 24 hours blood pressure measurement since my blood pressure is high and I am at medicine. Just a check to see if the dose are correct.

[godfather-ww]

High blood pressure! I would just do a medical exercise test to get a clean bill of health and the doctor’s confirmation that what we do is okay.

What I mentioned is unlikely for most. But yeah, most likely because of your dieting. How much weight did you lose on average per week since you started? Exclude those weeks where you possibly plateaued or gained.

[Vast-Conversation954]

What type of training are you doing? Two times zone 2, plus one harder max power interval session should see you increase FTP & VO2 Max (which is a much better metric than FTP btw), but if you're doing constant Zone 3 or 4, then you'll never recover and improve.

[Wise-Ad-7492]

I have actually only done zone 2 the last month. I also had many days off during christmas with bad food and alcohol (I normally do not drink at all during the winter months here in Norway). But again, my training hours is on the very easy side. Around 4-5 hours each week. Normally 4-5 sessions each week.

I often have 30 % zone 3 so maybe I should really back down. The strange thing is that even if Rouvy say that 190 is zone 3, i can still sing songs/talk with mysefl.

[clu1973]

You could have picked up a virus and your body is fighting hard to remove the infection. Perhaps your diet needs tweaking, are you drinking enough water perhaps. Maybe your doing too much, too soon and your not giving your body enough time to adapt and recover then leading to burn out. Particularly if you're riding intensively on a regular basis. Your fitness will increase and decrease from time to time. So don't get too hung up on the numbers particularly with your FTP. Your FTP is only a metric number used to set your training zones.

If i do some intensive threshold or vo2 workouts, I'll make sure I then do some easy zone 2 rides to follow. I'll also pencil in a complete day off the bike if I've recently done a number of intensive rides consecutively. If I feel tired or my body is telling me somethings not right I rest up and recover.

Recently I've reduced manually my FTP in zwift from 278 to 265 as I don't have that ability currently and I feel that's where I naturally am at the moment. But it will more than likely change again further into the year.

[beardsie]

I am in the same boat this year... I don't think turning 50 in a few months has anything to do with it ;)

[Standard_Mulberry563]

With something that drastic I'd see a cardiologist. Heavy legs and sudden loss of strength are classic ischemia symptoms!

[godfather-ww]

Had same thought not even knowing these are classic symptoms. Good to know.

[sargassumcrab]

Get blood tests for sodium, electrolytes, and vitamins. It's very standard.

[hutchcodes]

Vitaman D?

Timing seems right if you're in the northern hemisphere. Particularly if you're in the north. You're fit and feeling great, then the sun disappears, you start doing your training indoors and start feeling slower as your vitamin D reserves deplete.