Earlier quoted context omitted.
How many people put their phone in their "upper pockets"? Or even have "upper pockets"?
Many men? If you are wearing a suit, a smartphone makes the trouser pockets bulge a lot, so it's common to keep it in your shirt pocket or jacket inside pocket - Both of which is next to your heart.
1: https://www.fda.gov/radiation-emitting-products/cell-phones/... 2: https://www.heart.org/en/health-topics/arrhythmia/prevention...