This is for my wife. I'd like for us to ride together at least a little, but when she exercises she get tired. I mean REALLY tired. Fall asleep standing up tired. She can be active for long periods without a problem, but if she gets her heart rate up its all over. It's pretty flat here but if we climb one hill (false flat) she can pass out at the "crest".
She has some other health issues such as asthma but it doesn't have a chance to kick in before she's out.
Any suggestions about what she can do to address this?