Health bar continously decrease?

So i created a healthbar that decrease when my Enemy collides with my player , but the healthbar is decreasing just once , i want to make it to decrease continously when my enemy is colliding with the player.

Healthbar script :

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.UI;
 
 public class Viata : MonoBehaviour
 {
     Image healthBar;
     float maxHealth = 100f;
     public static float health;
     // Start is called before the first frame update
     void Start()
     {
         healthBar = GetComponent<Image>();
         health = maxHealth;
     }
 
     // Update is called once per frame
     void Update()
     {
         healthBar.fillAmount = health / maxHealth;
     }
 }

And enemy script :

     private void OnTriggerEnter2D(Collider2D col)
 
     {
         if (col.gameObject.name.Equals("Player"))
         {
             Viata.health -= 10f;
         }
     }