This research study wants to learn about Chronic Kidney Disease (CKD) with Obesity, and Heart Failure with preserved Ejection Fraction (HFpEF) and better ways to evaluate these diseases. HFpEF means that the heart is not able to fill properly with blood while it is resting so the amount of blood pumped out to the body is less than it would be if it was filling properly. The study is being done to describe the differences in how the kidneys handle protein and salt in participants with HFpEF and obesity compared to healthy persons.

Criteria for Cohort 1: Healthy Participants

Inclusion Criteria:

• Adults 18-75 years old
• Normal kidney function
• No heart failure
• BMI 25-30kg/m2

Exclusion Criteria:

• Diagnosis of chronic illness
• eGFR<60mL/min/1.73m2
• Pregnancy or breast feeding
• History of cutaneous or allergic reaction to iodine-based products of contrast dyes
• Hemoglobin levels <7mg/dL
• Acute illness or hospitalization event within 3 months
• Unable to stop NSAIDs
• Comorbid conditions: MM, amyloidosis, pheochromocytoma, SCD, metastatic brain lesions, advanced kidney disease, liver dysfunction, endotoxemia, hyperthyroidism
• Current use of nicotine or recreational drugs, chronic drinker

Criteria for Cohort 2: Obese Participants without HFpEF

Inclusion Criteria:

• Adults 18-75 years old
• eGFR >= 60 mL/min/1.73m2
• BMI > 35 kg/m2

Exclusion Criteria:

• Diagnosis of Heart Failure
• Diagnosis of chronic illness
• eGFR<60mL/min/1.73m2
• Pregnancy or breast feeding
• History of cutaneous or allergic reaction to iodine-based products of contrast dyes
• Hemoglobin levels <7mg/dL
• Acute illness or hospitalization event within 3 months
• Unable to stop NSAIDs
• Comorbid conditions: MM, amyloidosis, pheochromocytoma, SCD, metastatic brain lesions, advanced kidney disease, liver dysfunction, endotoxemia, hyperthyroidism
• Current use of nicotine or recreational drugs, chronic drinker

Criteria for Cohort 3: HFpEF and Obese Participants

Inclusion Criteria:

• Adults 18-75 years old
• eGFR >= 60 mL/min/1.73m2
• BMI > 35 kg/m2
• Diagnosis of HFpEF (chart diagnosis, LVEF > 55% on echo, H2FPEF score 6-9 or HFA-PEFF score 5 or 6

Exclusion Criteria:

• NYHA class III/IV
• Urinary retention screen +
• Mobility issues
• History of RRT or kidney transplant
• Acute illness/hospitalization in the past 3 months
• History of cancer, chemo, or XRT
• Pregnant/breastfeeding
• History of allergies to contrast
• Hemoglobin < 7
• Comorbid conditions: MM, amyloidosis, pheochromocytoma, SCD, metastatic brain lesions, advanced kidney disease, liver dysfunction, endotoxemia, hyperthyroidism
• Unable to stop NSAIDs
• Current use of nicotine or recreational drugs, chronic drinker

Community-dwelling ambulatory participants who have HFpEF and obesity. We will compare with health participants and participants with obesity but without HFpEF.