***I have updated my original post**\*
I should mention that I hate gyms. But I need to get in shape or I'm going to die early.
I'm extremely sedentary. I haven't had a job that requires being on my feet in years. I drive long distances for work, mostly emergency blood for transfusions to rural hospitals. I like my job and I feel useful. But my only hobbies are sedentary, and my work is sedentary, and I'm facing the results of years of basically sitting on my ass.
I'm about 320 lbs. High functioning autistic. I don't like people and I don't like going outside my house. I don't like getting off my computer. It's always something I need to make myself do, and I feel miserable the whole time. So it's been very hard to find motivation. I count my blessings that I've found a job that is basically an extension of my house (my own car) and with very minimal human interaction.
I use a cpap because my sleep apnea is so bad the doctor said I might be suffering brain damage, bad enough it might have killed me if I hadn't gotten it treated. I know obesity makes that worse. I suffer from sexual dysfunction and lack of libido, and it affects my marriage.
But my body is just falling apart. If I do something too strenuous, like walk up an incline, I feel like my blood can't pump fast enough. I'm not even necessarily out of breath, my lungs are fine. But my pulse skyrockets and I start to feel lightheaded. It can take 5-10 minutes of standing there, breathing deeply, for the feelings to normalize. I feel like I can barely exercise because of this. I worry about passing out, about not getting enough blood to my brain.
My diet is relatively good, oddly enough. I'm a good cook and I cook homemade meals from raw ingredients. I don't eat much meat, and I like my fruits and veggies. I rarely have seconds or snack on anything but fruit. It's a testament to my absurdly low level of physical activity that I've gained as much weight as I have. I'm hoping any level of activity will show results.
So I joined the nearby gym. I just have to scan a qr code on my phone. I don't have to talk to anybody. I can put on my noise cancelling headphones and listen to an audiobook. I don't listen to music. But it's still mind numbingly boring. I hate it. I don't like moving around.
I managed to use an elliptical for 30 minutes, but it was on the easiest setting and I didn't realize until I got off how light headed I was. My legs hurt. I have bad knees so I wanted something low-to-no impact. I tried going back the next day, but I could only last 15 minutes on the elliptical. I think I was still recovering from the day before.
Am I doing this right? Is any level of physical activity good for me, at this point? If I can only manage 15 minutes, or 10, or 5, that's still better than nothing, right? I want reassurance that if I keep going, I'll get better at it, and be able to go for longer.
But I also am pushing 50. I don't want to overdo it. I don't want to hurt myself. I feel like 30 minutes of cardio on the easiest level should be safe. But how will I know if it is too much?
***
update: I really appreciate all the encouraging words. I have read every single one of your responses. You are all very kind and inspirational. I liked reading about people who were also my size and have lost weight.
I will try to address some of the more common questions and comments you have been making.
One of the reasons I joined a gym instead of trying to exercise at home is because it is very easy to procrastinate at home. If I'm playing my favorite video game I can easily lose 3-4 hours without realizing it. Then I get distracted by all the things that need to be done. The same thing happens if I try to do online classes. I really need a separate time away from the house so I don't procrastinate or get distracted.
I used to go walking and hiking in the nearby foothills. I like birdwatching. That was years ago. I tried doing it again and I couldn't make it very far at all. The hills and ravines were too much. I started to have anxiety visions of collapsing out of view of other people. Birdwatching is good for me because it gamifies walking. But I feel like I'm actually too out of shape for it. I need something more tightly controlled where I can slowly incrementalize my progress.
I have tried gyms before, but that was a long time ago and feels like a different lifetime. It's how I know I hate them. I didn't go for very long.
One of the reasons I'm focusing on cardio is because I'm worried first and foremost about my heart. That's what kills people like me. Lifting weights might help my weight loss and make me stronger, but I'm worried it won't target my heart.
You are all probably right that even if I eat fairly healthy foods I am probably eating too much in terms of volume. Ten years ago I ate a lot more than I do now, but I weighed much less. One of the reasons I feel like my diet isn't that bad is because I'm comparing it to my own food history. I'm guessing this is just what aging is like.
I'm not planning on taking weight loss drugs because they're not covered by my insurance for weight loss. If I was diabetic I could get them, but somehow I'm not. My doctor was surprised that I'm not even pre-diabetic. I'm also worried about some things I've read about how you need to take the drugs for life and regain all the weight if you stop, and that just feels like a trap to sell more drugs.
I do not want to take classes or get a personal trainer. Based on my previous life experiences, I am unlikely to go at all if there's an expectation of human interaction. I'm almost 50 and I've been this way since I first left my house for school as a little kid. I get panic attacks and cannot think clearly. Decades of exposure with typical classes and jobs never helped, I just dreaded every single day. It's just the way I am. That's why I use the noise cancelling headphones. I look at the screen right in front of me and try to tune out the rest of the room.