TL-DR version - Any sense of swelling in your legs, get it properly checked.
Fit, active people may not show symptoms in the way sedentary folk do? I certainly didn't. Doctors may well dismiss certain causes because you're a generally fit and healthy person but it's good to know the signs of things that can be serious, perhaps be a bit pushy at the early stage. Don't think best-case positive "I'll be fine!", or get into a dark place thinking about the worst - either way you may miss something rarer but still serious.
Early last week I was in hospital overnight after going to A&E because things weren't right. I had bilateral pulmonary embolisms, moderate level blood clots in my lungs. My neighbour's friend died of the same thing only recently, though I'm assuming it was a more severe case. In hindsight signs were there but when things are happening and you're fearing something far worse as well as the symptoms being easy to attribute to simpler causes, maybe you don't think straight.
All in all, if the clot risk was realised earlier I may not have gone for a ride that may well have dislodged it or forced some of it into my lungs where it became a more serious problem. Or, it getting into other areas where I'd rather not think about the outcomes. I feel lucky and thankful.
Posting in case this helps someone else recognise or avoid a similar situation. Plus for a bit of cathartic relief I suppose.
- About 8 weeks ago I went for a short trail run and after I got back I felt a mild pain in my calf. I thought I'd pulled a muscle. That night there was a pain point deep in the calf but nothing severe. A few days later we drove to Snowdonia for 3 days camping and hiking. We walked up Snowdon, around Ogwen valley and I had an easy day exploring the Bedgellert to Llanberis Pass valley. No sensations of calf pain, no sense of doing any damage. In hindsight perhaps it should have seemed odd that any muscle damage healed or disappeared so fast.
- Soon after getting home my calf felt sore in a pressured kind of way when walking and swelling up. I got it checked for DVT at the local surgery on someone's recommendation 'just in case' and they said DVT was highly unlikely and the main or obvious symptoms weren't there. So to me this was simply a swollen calf - pressure on a vein from a muscle swelling perhaps. Over the next weeks it would swell if I stood up or walked a while, or a long day driving to/from office with desk work, but reduced fast with elevation. Maybe 5 weeks later the swelling was gone and I was riding as normal. Seems about the right time for a muscle issue to recover, I thought.
- 3 weeks ago I'd got new shoes and pedals on my bike and felt like my hip/bike fit related pains on climbing were resolved, I had a Sunday morning of going all-out on a few local hills and long drags until I had to stop and slump over the bars to get breath, enjoying the feeling of being able to max out again after a fairly long period of fit issues giving me on/off ability. In hindsight my breathing was maxing sooner than my heart rate, I put it down to a general lack of top-end fitness. I'd done hill reps 8-9 weeks before and felt ok at my usual threshold HR.
- That night and for a few nights after my ribs were giving me gyp and I had that intercostal muscle strain feeling. Had to sit up to sleep and take Paracetamol. Thought I'd wrenched muscles by hauling on drop bars and the forced breathing almost to the stage of collapse. That pain reduced steadily over the next week, backing up me thinking it was muscular strain.
- Odd mild fever symptoms started soon after the rib pain but my wife also felt ill a few days later, so any fever that may have been linked to inflammation I'd written off as a mild cold, one of those odd low symptom but feel groggy colds that go about these days.
- The scary bit was when I saw a bit of blood in my morning phlegm a day or 2 after that initial 'muscle strain'. Maybe a ruptured blood vessel breathing so hard? Then it happened almost every morning for about a week, it wasn't going away, probably wasn't caused by the hard ride. The hard ride maybe just revealed something? I wasted a few days hoping it would 'just stop' as if it were a bleed then heal thing, probably stupid I know. Called 111 on a Friday afternoon, spoke to local GP and was told to call for a chest X-ray on Monday am. For context I smoked when I was a student and cycling faded from life for a while and that was part of a profile the Dr gave as a reason for the x-ray. Called them 9am last Monday, they had me booked in for 10.30am. Results can take 2-3 weeks they said.
- I went to work the next day, up at 5 for an 85 mile drive so I usually stay over and I'm there for 2 days. Was in contact with the local surgery by 10am due to the ongoing symptoms inc the blood and tbh I was feeling rather odd, really not myself and I was scared. They said I should go to A&E.
A&E took blood for tests, I told them about the calf swelling, the hard ride, sore ribs and then the blood in phlegm, they did an X-Ray then a CT scan 'to look at something in my lungs'. A couple of hours later I was taken into a doctor's room and they told me I had blood clots in my lungs. The rib area pain I'd had was pleuritic chest pain - combined with the blood there was a clear sign of pulmonary embolism at least 10 days earlier. I wonder if the local surgery could have picked up on that sooner but I don't think it would have changed where I am now anyway.
Look after yourselves..
So many things about getting old petrify me. 
