This is a repost of a self case study I did in January 2019 regarding correlation and regressions with sodium and blood pressure.
Introduction Genetically, I have borderline / high blood pressure (hypertension stage 1 or 2, (source). I don't currently take medication and would like to keep it that way, so I'll be examining several dietary changes and their effects on blood pressure. Heart Rate and Blood Pressure Values "Normal" blood pressure (BP) is defined by the American Heart Association as 120 / 80 (source(, say 122 / 81 for a 30 year old person. So, that's my goal -- again "unmedicated." Resting Heart Rate (RHR) is also important -- think of low blood pressure and high heart rate as redlining a car's engine while in neutral. For a 30 year old person, under 75 is "average", but under 60 is "excellent" (source). Intervention: Sodium and Hypertension The FDA suggests keeping sodium intake under 2300 mg / day (source), but the American Heart Association suggest reducing sodium potentially as low as 1000 mg per day for those with high blood pressure (source). My target intervention, then is to keep my daily dietary sodium intake under or as close to 1000 mg as possible. Typical measurements were taken after being awake 5 - 6 hours. I typically dring 2 - 3 cups of coffee per day, half first thing in the morning and half mid-day. Measurements were taken after the mid-day dosage. Results: Preparing all my meals at home was the only way this was remotely possible. The smallest convenience meal (e.g. gas station or convenient store) in a pinch would greatly distort an entire week's worth of data -- that is not even to mention trying to socially eat out now and then. However, staying under 1500 mg / day or certainly 2000 mg / day is easily attainable with much more "lifestyle" flexibility. It is also worth noting, as I did in previous posts, that athletes need more sodium, and my activity level has greatly increased in the past few months (i.e. more sweating means more electrolyte loss and greater need for higher consumption). | Date | Systolic | Diastolic | RHR | | ------- |:--------:|:---------:|:--- :| | 1/3/19 | 144 | 88 | 77 | | 1/9/19 | 148 | 91 | 78 | | 1/15/19 | 144 | 88 | 75 | | 1/20/19 | 133 | 81 | 78 | Conclusion: As you can see, drastically reducing sodium intake didn't have a large effect on my blood pressure. Of note, the last reading -- while it is notably lower -- was done on a different machine than the previous readings. Overall there is not much change (see weeks 1 and 3). However, it could also be the case that 4 weeks is not a long enough duration to significantly effect blood pressure. This is the first in a series of blood pressure related posts where I'll be looking at different dietary measures to reduce my blood pressure.