I'd say you ae doing it all wrong. Working extrmely hard means anaerobic. I do lot so hills. I do a good efort but as I crest a hill, I drop the gear and spin FAST at an over the top!
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I fyou are trying to strengthen the legs to lose weight, makes no sense. You should be trying to spin (high rpm's) in a lighter gear. GO aerobic for longer periods of time. That will make you lsoe weight, not hard weightlifting type efforts.
If you notice fast hill climbers, they aren't pushing big gears, they are spinning at a high cadence. At 230, you have the strengh, you need the heart and legs conditioned to move fast.