How can I get fit?

[AntiHop]

I'm unfit. The only exercise I've done regularly over recent years is pilates and yoga and I've not done that regularly lately. I don't think running would be good idea as I'm overweight and I'd worry about my knees. I don't have a bike and don't feel confident cycling.

I'd like to develop my cardio vascular fitness. Any ideas please?

Swimming is good but you can't just people along you have to put effort into it. Walking is the best to start with - you can increase your pace and tackle hillier terrain as you get fitter.
Losing weight helps make it easier - small changes will add up.

Take it slowly, start with walking than a bit of jogging.
C25k is great
Do some various exercises at home
Jumping jacks to get your heart rate going even if you can only do a couple at first .
There are loads on YouTube but take it slowly and just build it up .
30 minutes walk a day to start .

Walking is definitely the best activity for getting started into exercise - not too strenuous on joints, free, can be done anywhere, can tie it in with daily activity. And as a previous poster said you can gradually increase intensity by walking faster or on hillier terrain.

HIIT workouts at home - look for one with minimal jumping if you're worried about knees. Don't do couch to 5k for same reason. Running is a great free exercise but not good for the joints.

HIIT workouts and substitute any jumping with either none or simply jumping your feet together and out.

Avoid hiit altogether IMHO. Walking and strength exercises with resistance bands are a really good combo as it's hard to overdo it. Get a step counter or the app "active 10" which is an NHS app which gives you credit for brisk walking rather than just how many steps you make in your house over the day. Build walking into your day, walk places you'd only have previously done in the car or on the bus. Get some earphones and find some interesting podcasts and the time will go in no time. Walk as fast as you will feel your heart beating more than it usually does while walking. For resistance bands, get a few and find out how to do some exercises on YouTube. Its really easy to do at home and important to supplement heart-rate-raising exercise with ones that'll challenge your muscles.

Walking is good but it's not going to get you fit and it's very time consuming. You'll burn more calories and condition much more quickly with a 45 minute HIIT workout 3 times a week than walking hours every day.

I do HIIT workout a few times a week but it will be hard going at first if your unfit .
Some people try to do too much at first and find they can't keep up but keep going it gets easier .
That's why I'm saying start with walking try HIIT too but you will burn calories with walking .

Walking won't get you fit!? Wow. That's some terrible advice and against all the scientific advice that it's the best exercise for the heart and very good at burning fat as it keeps your heart rate below 120bpm.
Hiit is very likely to give you an injury if you haven't done much exercise previously. Walking is literally useful, put it into your daily life and you won't have to move your coffee table and jump around in your living room.

How much walking would a person need to do to get genuinely fit?? Several hours a day. It's ineffective. It also fails to provide any progressive overload so there is a limit to how fit anybody can get by walking.

Walking is a very good start until the pools open

But @CodenameVillanelle walking is an excellent place to start which is what the OP is looking for. Pace can be increased. Hills can be included. Plus, it gets you outside which is brilliant for mental health and vitamin D. Also, more long term it becomes part of your lifestyle - you start walking places instead of jumping in the car or on the bus which long term is much better for you and to sustain any changes they have to be part of your lifestyle. Much better to have walking as your basic something you do every day, her starting point, that can be increased in intensity etc and then add in Hiit workouts as she goes along or start C25K etc, rather than start with the workouts not keep them out and be exactly where she is now

Instead of recommending a specific exercise, I’d say try lots to find 1 or 2 that you like.
You’re much more likely to stick with it if you enjoy it.

I hate all forms of exercise, but discovered surfing and tennis last year. Now I’m miserable that I can only do them twice a week!

Don’t do Hiit workouts or C25k if you have bad joints - you’ll end up with an injury. Check YouTube- there are plenty of stretch and tone workouts which won’t damage your knees but will improve your fitness.

Brisk walking. If you are going to supermarkets you could walk there.

Take a look at Fitness Blender easy workouts on YouTube.

@CodenameVillanelle the OP says she is unfit. Walking briskly is the best exercise to get you fitter without injuring yourself. It's ridiculous to start talking about progressive overload until you're fit enough to go further, deeper and stronger with your exercise.
Once you've fitted in walking to the shops and and a walk to the park, you'll have done a decent amount as long as it's raising your heart rate. It doesn't take hours, 30 mins brisk is worth dawdling for an hour.

Thanks very much everyone. I'll start with walking. I used to do a lot of walking that I could easily incorporate into my job. Then I changed jobs and had less opportunity for walking. Then lockdown has reduced the walking further. I was thinking of buying an exercise bike too.