i have an appointment today. last night i had a more normal meal than i have had last few months an hr was 45 or so after the meal. could be too much of a good thing. he will figure it out
Your baseline heart rate of 40 beats per minute is likely attributable to your high fitness level. Based on what you have documented, it sounds as if you had no symptoms at this heart rate. The recent decrease in your heart rate and the dizziness you experience with standing merit closer examination.
The dizziness with standing might be due to dehydration, as you have been trying to lose weight is it possible you have cut back too much on your fluid intake? This is potentially more of a problem with running outdoors in the summer months. If you have been aggressively cutting back your calories to lose weight, it might also be that you sugar levels have dropped a bit lower than you need, although this should not cause symptoms only when you stand up.
To get to the bottom of things your doctor will need to review your history in detail, including any new medications or medication changes. With regards to the slower heart rate, your physician will probably also opt to do an EKG/ECG to have a look at your heart rhythm in more detail.